Yea not opposed to Siro to 13 with Jazz and Harris permanently on the Edge. He is too creative for 13 for me even if he loves the actionI personally don't see Siro as an edge backrower, he's only mid 90's and doesn't have that punch you want on the edge.
Katoa not too worried about currently, he will come right hopefully just needs to refine his game in reggies for the moment.
Murch has shown he has all the tools, just needs to bring some consistency. Actually thought he looked primed in that trial, but hasn't brought that form into the season yet.
You are right about Curran, whatever rocket he got given it seems to working.
All four are still really early in their careers, with a lot of growth hopefully still to come. Hell 2 years ago I was like a broken record asking for a decent 2rf to partner Tofu, now we a bunch just need to find the right pair.