I agree with a lot of your opinions here, especially about Phastos. Really not expecting much from him.
Well good for you. But like I said the other day; some of us have been waiting long enough and aren't thrilled with the idea waiting for a couple of ten year-olds to age into the roles. But you are right when you say that's an unpopular opinion.
That being said I highly doubt that they are going to wait for the child actors to grow up because:
1.) It really looks like they're doing the convoluted reincarnation plot after all.
2.) Just because those boys are decent child actors it doesn't mean they're going to be great actors when they get older. There's different expectations for acting with a child's role as opposed to from someone older.
3.) I might be wrong about this but I think they're gonna' want to cast openly gay actors to play Wiccan and Hulkling, especially after they made sure to cast gay actors for Phastos and his husband. At least I'm really hoping they cast openly gay actors for Wiccan and Hulkling, I know this is a huge can of worms among straight people but I think it's important.