Kioku's thorough reply is correct, and quite near complete. Additionally,

Arrow + Fey Wind (Selene's Haste buff) stack.

If two ASTs use Collective Unconscious, the damage reduction is only applied once and only one regen applies, but if a party member stands in either bubble at the time the server ticks, the duration of the regen will be restored to max (15s).


The behavior of the AST regens is noteworthy here because two separate ASTs cannot both put up all their regens, as was suggested in previous replies.