I heavily dispute this reasoning. In this case, first, they had enough time to put the Chorae back on after ultimately going with Kelmomas. Second, it is absolutely unclear that the Chorae would even damage the Insertant, since the Carapace is thick enough to serve as protection - the Chorae are on the outside of it, while the Insertant is inside.
Well, I was slightly incorrect, it's Kellhus thinking this is why, not them saying it. In any case though, I am not sure why you think they'd have that time though. I mean, from our abstract, third person knowledge, we do know they likely have plenty of time, but they stuff little Kel in there post-haste, so they seemingly don't think they do. We also have no idea how the Chorae are affixed though, so we don't know really how long it would take really.
It's easier for me to believe the Consult/Dunsult is ignorant of how to start the No-God than it is for me to believe they're just pretending to try to kill Kellhus to lure him in. All the while ignoring any of his more accessible offspring or ishualian relations for 20 years.
Well, I think you are 100% correct, they do not know, they are just guessing. But, I'd still contend that they (for whatever reason) consider it likely that Kellhus is the "right fit" or, at least, not the wrong fit. In other words, since they have no real idea what makes it work, they are looking to try any and all ideas. Which might explain why they take the Chorae off, in case Serwa needs to go in, or whoever else is left. They also have no idea if the Chorae might kill the Insertant or not, so why risk it?
Speaking of the Dunyain all having Anasurimbor blood - I think Bakker is making an effort to counter this argument when he talks about the Twelve Germs (if memory serves), of which the Anasurimbor one is the most promising. Since the Germs are pointedly named as different from each other, I get the idea that the Dunyain in their generational selection quest were strict about keeping the lineages separated.
Yeah, I agree here very much. I do not believe that all Dunyain are Anasurimbors. In fact, I think it is very much the opposite case, that they were actively working toward isolating the lineage into that one germline. Whether that is of some "mystical" importantance or a way of distilling out the distant Nonman relation, who knows though.