I agree with everything except the bolded parts.
Mard and Elfman are the ones I can see why you would think they are near her level of durability/tankiness, but I wouldn't put them on her level. Skullion doesn't really seem to damage people that much outside of outright one-shotting via Black Ash, and Madmole is only really an issue because the dude is crazy tough to damage (not saying his offence is bad). From that I feel confident in saying that there's no way Elfman has tanked enough damage to compare to a Secret Art from Laxus. As for Mard, he had crazy durability and endurance pre-skip but I'm not convinced that's enough to compare with 100YQ levels. I guess it depends on if you think he could tank a Secret Art from 100YQ Laxus. Personally I don't since it was made very clear just how much the main cast improved over the time-skip. I mean Laxus went from extreme-diffing Jura in GMG to killing a supposed equal of Serena's with one spell and beating Hades while completely exhausted.
But the ones I really disagree on are Sting, Jura and Jacob. I love Sting from the bottom of my heart (my fav character aside from Jellal and Bradman) but, at least for now, there's no way he's tanking what Kyria took. He was getting wounded by Larcade's physical strikes and only really won their fight due to numerous beneficial factors. Jura shouldn't be anywhere near Kyria in durability, Serena massacred him and 3 of his superiors once casually and then again once he got serious - and 100YQ Laxus should absolutely crap on Serena's offensive output. Finally, Jacob would get outright killed by Roaring Thunder. An FDKM Demo Fist from Natsu one-shotted him, we've seen August says a nameless nuke from Laxus would kill Ajeel and most importantly we saw how Laxus immediately killed Wahl when he could actually affect him with Magic.
The reason I'm thinking that Jura isn't totally powercrept is because Makarov is still seen in high regards. And I see Jura in the same level as Makarov.
Serena is just that strong. The fact that he overwhelmed base team Natsu with just a fraction of his power speaks for itself, and he made Gildarts use his finisher move series. Just his headbutt with Gildarts blew away team Natsu and made them comment on the magic power (and they were already used to the 'typical' Spriggan magic power). All this from a historia.
Of Course Jura got rekt by the original.
Mard took negligible damage from anything that's not devil Slayer spell. Including POF + DF Natsu, and CSK (whose attacks were destroying mountain ranges, Mard just used his energy shield casually in base).
Mard was waay above anyone in that arc. He was like the August of the arc, nobody could touch him (except for Gray with his Slayer powers).
And now to that, add the fact that he can even regenerate (as he did when Gray damaged him, the entire reason why tartarus could revive demons was because of his powers as mentioned by them). He's an absolute tank.
It's implied that full power Mard = full power CSK, maybe once we see CSK at full power (if) we'll know how strong Mard truly was.
Laxus isn't shitting on Serena, unless you think Laxus is shitting on Alverez arc Gildarts. I said more of Serena in my first para too.
I see Alverez Gildarts > current Laxus, and same applies to Serena.
Larcade's magic power is said to be comparable to August and Eileen. Sure, his physical stats are trash (relative to his magic power, the typical Spriggan with high magic power and hax); but it was good enough to fodderize Kagura's archenemy. At least it's something. It's good enough to put both Larcade and Sting above Kyria who basically got fodderized by Laxus who barely moved from where he stood.
None of them killed Erza, it? To be completely honest, Laxus hype train went down for me from that fight. Erza struggled against Ajeel and was beaten by three historia from Neinhart. But she, albeit with external buffs, managed to give my boi extreme diff.
I was elated that he won, just cause she's fucking Erza, the queen of bullshit; but broadly speaking I was disappointed.