I don't think Sub or Bara had a hand in Genthru's Countdown. Abengane deduced that Genthru was extremely skilled in Materialization, Manipulation and Emission, and that's why he's definitely a very powerful fighter which they couldn't take head-on. Nothing seems to contradict that. After all, Koltopi's ability is also Materialization, and it doesn't seem to have any problems with keeping the objects away from him. My theory on that is that Materialization users, if extremely skilled, can use conditions to avoid the Emission issue. Both Genthru's and Koltopi's techniques certainly have their restrictions.
I think Goreinu's creatures are materialized because of the reasons I stated in the other post. Razor felt the need to comment that Goreinu's creatures disappeared when he was KO'ed because he was manipulating them and it wasn't obvious. I think Razor's creatures (and Emission Nen creatures in general) are independent, and require next to none Manipulation. I think if Razor was KO'ed, his creatures wouldn't (necessarily) disappear.
Also, based on Wing not mentioning Kastro's Emission skills (he wouldn't have any problems since he is a Reinforcer, but still, Wing didn't even mention it), I also have another theory: materialized Nen "creatures" -like Kastro's clone and Goreinu's gorillas- don't require Emission. That's because they're already made "real" away from the user. It'd be pretty ridiculous to be able to materialize creatures that would need to be stuck to you the whole time, and since Emission is the polar opposite from Materialization it would mean materializing Nen creatures would be a mistake.
Nothing contradicts Genthru was skilled at Materialization, Manipulation and Emission except for the fact that when you are a Materialization user you will suck at Emission. Kurotopi's objects are limited by the fact that they don't last beyond 24 hours, so they can't be expected to be carried very far from the user.
But still the main point of Goreinu's gorillas were that they were maintained far from from him and they were pretty independent. Some things a Materialization user can't really do. Add to that that the special ability of the gorillas were to exchange places with their targets - something that pretty much requires Emission because of the distance involved.
Doesn't help your argument that Wing didn't mention Kastro's Emission skills. It should be common sense at this point that you are going to have good affinity with Emission skills when you're a Reinforcement user. Just because Wing didn't say it doesn't mean Kastro didn't have to use Emission when he clearly needed it at the very least. What helped him was that he didn't have to permanently Materialize the Doppelganger all the time he needed to use it - he just made it appear when he needed to use it.
If it was ridiculous for materialized items to be stuck to you the whole time then why did Kurapika had to mention that he needed to use Emission to materialize his chains stuck on targets that are extremely far away from him (Paku, Kuroro)?
Sabu and Bara's part on Countdown is more likely not limited to getting a sooner explosion because a Materializer basically sucks at maintaining things from far away. Abengane did not know there were two other guys involved with Countdown so he thought Gensuru was good at both Materialization and Emission which is not a good way to train Hatsu at all.
About Netero (2): If Netero was Reinforcement, it would be quite foolish to develop an ultimate technique (Zero) that isn't based off of it, since Zero is clearly an Emission blast. There's a huge drop in power. Even if there are huge Mystery Point bonuses given by pouring all your aura into that blast, there's still a clear advantage in just using a Reinforcement-based ultimate Hatsu technique. I'm pretty sure Netero took that into consideration.
Also, 10 years of training non-stop is not a restriction for Kannon. Netero just followed the natural path of learning Nen, or, "taking our time", as Wing said in Chapter 48 page 3.
Additionally, here is an interesting bit in how I think Netero formulated the Shingen way of learning Nen, and eventually, Kannon.
We all know about the four basic Nen skills, Ten, Zetsu, Ren, Hatsu - as mentioned in order by Zushi in Chapter 46 page 7 and Wing in page 9 of the same chapter.
Now, observe a future chapter: Chapter 265 pages 4-5.
On page 5 we see Netero doing the cycle he goes through before releasing the punch. In my translation it says: Preparation, Worship, Prayer, Readying, and the Thrust.
If we align the basic Nen skills and the cyclce Netero uses, we find that they are roughly the same.
Preparation and Worship stages roughly coincide with Ten.
Prayer roughly coincide with Zetsu.
Readying roughly coincide with Ren.
The Thrust roughly coincide with Hatsu.
By consolidating all of this into a system he basically hit upon the Shingen-style Nen teaching.
By repetition of this cycle Netero has come up with his Hatsu, Kannon, which appears only after a punch, or, a 'Thrust' has been released.
We can clearly see that in one cycle moving towards the release of even one Thrust or the Inflammation of Spirit, Netero has encapsulated the whole Shingen training program.
We can clearly see that through this rigorous cycle for a decade, Netero has effectively erased the need for a "restriction".
And in this light, we can see that the whole cycle of releasing a Thrust is not a "restriction", but a way to make oneself "feel better", similar to how Gon has to scream the words "Jan Ken xxx" before release.
