I'd like to see more characters for each of the cities factions (wanderers, freeguild, ect) I'd also like to see units of mixed races that can choose between the different factions similar to slaves to darkness
So I started collecting the old wood elves before age of sigmar launched and I absolutely love the lore for the Sisters of Twilight. Unfortunately I never found out what happened to them when the world ended. Did Slaanesh eat them or what happened. I'd very much like to know if they might have survived and could possibly show up in age of sigmar.
One of the biggest things you need to do to get is check with the tournament organizers and see if they are ok with them being on different base sizes (I think Phoenix guard are on 25mm and cypher are on 32 but double check) I would personally remove any chaos markings but honestly it's a conversion so do what your heart desires!
I haven't purchased any spite revenants yet so I'm not sure how good they are in battle. As for the branchwych vs archrevenant and branchwraith it depends on if you want to summon dryads (I've been pretty successful with my summons) or boost your hunters, I tend to use my branchwych as a extra caster. I think they're all good choices it just depends on what kind of support you want