oke also said that Lucy's regulus Lucy kick contained some of his light magic.
You're always confusing allowing her to use their magic with giving her more magical power than she would ordinarily have. Star Dress allowing Lucy to use her spirit's magic is the same as Hibiki downloading Uranometria in her head or Romeo learning how to use Fire Magic, or on a more extreme example the would be something like Rufus' Memory Make or Hibiki's Archive allowing them to use pretty much any magic they have in their memory/database. When she star dresses a spirit she can use the same kind of magic they have. It is just that, it is not that she receives more magical power than she already has just because she is star dressing, rather it is that it allows her to use other kinds of magic other than her regular Celestial Spirit Magic.
Lucy's magical power replenished from near exhaustion to fighting condition because she received Aquarius' magical power. That's not really out of the ordinary. [...] I don't see why Aquarius' star dress must be considered the exception.
We know that it is possible to use certain kinds of magic to replenish someone's eternano container, we have seen that Wendy and Shelia have this kind of ability, as well as all dragon slayers and god slayers could do it by eating the element of their magic. Even so it is not a power that anyone has access and it seems that it isn't very common at all, even though it doesn't seem to be very rare too.
So even though the act of replenishing someone's MP isn't that much out of ordinary, but the situation in which it happened to Lucy actually is not because she was receiving MP from anyone else, but because she was receiving MP from something that actually needed her to give her MP in order to function in the world she is in. To make an analogy, what you are proposing it is like a car that uses gasoline, but could give some of the gasoline it uses back to the fuel tank.
Another reason why when she used Aquarius Star Dress should be viwed as the exception rather than the rule, is the amount of power it was shown that Lucy could wield during that fight compared to later uses. While using Aquarius she was shown to use Aquarius powers almost at the same level as Aquarius, while the other times she used star dress it was always shown as a useful but weaker version of the power her spirits could use. So it clearly was a more powerful version of the Star Dress.
The fact that both the replenishing and the increased power level only happened once when the CSK had given her Aquarius power when she doesn't had enough MP even to continue using magic, means that it isn't a situation that should happen very often.
Actually we have evidence that they could not normally do such things because more than once Lucy was out of MP and Virgo and Loke had to use their own power to come back and save her and after that they could not donate a single drop of their own MP back to her in order to allow her to fight, they always ended up taking her out of the fight and asking her to stay there and recover.
So my point is not that she could not receive MP from her spirits at all, but that it doesn't seem to be something they could do often because she already have been in similar situations and they couldn't do it, they always saved her, put her somewhere safe and ask her to recover instead of just replenishing her MP. My hypothesis is that they simply couldn't do it because they need that she could use her MP in order to stay out of the Celestial Spirit World.
It's debatable who is stronger between Loke and Aquarius. Lucy herself said that Aquarius was her strongest spirit when she summoned her. Aquarius also handled Jackal a lot better than Loke and Aries did tbh.
Leo is the leader of the 12+1 Zodiacal Spirits and second in command only to the Spirit King, Lucy stated before that Leo and Aquarius were the most her powerful spirits, but never ranked them, and them we have a statement she said on a desperate moment after her other spirits were defeated. In the end, until something more substantial is clearly stated that Aquarius is stronger than Leo, the evidence are leaning more on Leo's side than on Aquarius side.
I didn't say that Lucy doubles her magical power when she uses star dress. If anything, I'm saying the opposite. Not many of Lucy's spirits are as powerful as Lucy individually, so not many star dresses can double Lucy's power. I did say that some star dresses has potential to double her magical power.
You do think that this is a contradiction, you know you say you didn't say it doubles her power, that it is the oposite, them of state that it has the potential to double her power. It either increases/double her power (de facto or potentially) or it isn't, there isn't much middle ground in the kind of statement you're making.
For example, a CSK star-dress should rightfully double Lucy's powers otherwise it would be extremely underwhelming. The magical power isn't coming from nowhere either. It's coming from the spirits themselves. The more power she takes from the spirits, the less the spirits themselves will have for themselves. Do I believe Lucy is doubling her magical power when she uses Aries star dress and has Aries summoned? No. The total amount of power between the two is still equal to Aries + Lucy, it's just that now they can share the MP more effectively.
Here again is a case where you confuses magic's power with magical power.
Magical Power is the amount of eternano particles Lucy has at her disposal and of course if she has more eternano she could use higher level spells, it also allows her to use these spells more often.
Magic's power is the power is the power of a given spell how destructive or how strong it is. The two concepts may work together, but they also couldn't. For instance, when Lucy uses Uranometria she is clearly using one the most powerful spells ever created, it doesn't matter how much MP she has Uranometria wouldn't be more powerful because of that, but she certainly would have enough power to cast it by herself, without Gemini's help and she would also be able to use it more than once.
A easier way to understand it is comparing it with Erza's magic. Erza could summon Fairy Armor, Nakagami Armor and Adamantine Armor, all of these armor allow her to perform very powerful "spells", but the amount of magical power she possesses continues the same, it didn't change, the stronger armor actually consumes more of her MP and she have to use them just for a limited amount of time.
In Lucy's case, if she get a stronger spirit's Star Dress, like Leo, Aquarius and even the CSK (if it is even possible), she would be able to perform magics that are more destructive, but the amount of MP she would have would be the same, so whenever she uses these more powerful magics with Star Dress, will means that she will have to use them for a shorter amount of time.
The war god was summoned by Arlock with summoning magic. Specifically, the Yakuma 18 battle gods magic. For the sake of simplicity, I see no reason to assume it works vastly different from Celestial Spirit Magic. Also, War God is not weak. The attack that took him out was the same attack that took out a Spriggan 12. At the very least, War God would have been stronger than Bluenote, who is probably comparable to a WS like Jura. Secondly, the more important part is that War God is obviously stronger than Arlock himself. Arlock himself was defeated by a single blow by Natsu before he summoned war god. War God survived an attack of the same magnitude, and forced Natsu to use FDK spells. I don't think it's at all unreasonable to assume that a summoner can summon something stronger than herself. I consider both Loke and Aquarius to be stronger than Lucy individually. Star Dress changes that dynamic now though.
Again, you're confusing MP with the destructive power of a certain magic/summon.
I said that Arlock have low MP, so anything summoned by him that have more power than him could not be summoned with its full power. The destructive power of its magic could be high as hell but it could not use it's more destructive powers.
Again let's use an analogy, if his maximum power is Fire Dragon King Mode and he was summoned by someone weak, like Romeo, he would be able to perform just the normal fire dragon magic (which is already very powerful), but if he was summoned by someone stronger, with second origin, like Lucy, he would be able to use lightning fire dragon mode, but if he was summoned by someone like Erza, he would come with access to Fire Dragon King mode.
Since it is implied that the MP of the summoner limits the amount of power the summon could wield, a weak summoner could not summon something far stronger than him with its full power, just a limited version of it.
(I just hope she shows Aries form.) And I do think that the Leo one is stronger than Taurus considering Loke is stronger than Taurus, its just that once again like you said she never shown the extent to that one compared to her Taurus form.
