Quote Originally Posted by MagiusNecros View Post
Won't happen because the recasts are different and AC and Gluttony are Abilities while PH and Communion are a weaponskill and Spell respectively on the GCD.

Edit: I do understand your concern for Reaper though. Button bloat is going to be a thing since for controller players such as myself the full kit of Reaper requires 24 buttons at minimum. Not including Limit Break, Sprint and any associated Role actions.
I don't think it being ability or weapon skill, or even different cooldowns play any role in whether they can turn into each other. GNB Continuation combo is a mix of weapon skills and abilities, and it is all on one button come Endwalker. DRG Geirskogul and Nostrond are on different cooldowns yet share a button.

They likely will not do this on reaper for those specific abilities.