i think i understand the reasoning but need to clarify why i have a doubt here:
The general rule is, when during resolving an effect due to a trigger an effect get added to the list of effects applicable for that specific trigger, the added effect is usable to the actual triggering already. Correct so far?
So under Innovation there is one effect lingering to "when a card is gained". Gaining Livery and playing it with Innovation adds another effect to the same trigger and due to the general rule gets resolved immediatly; the Livery provides a Horse for its own gaining. Still correct?
I understand GendoIkari's answer to the Priest played during resolving Catacomb's trashing effect adds Priest's bonus effect for trashing to the list of effects usable to trashing Catacomb and so gives $2 for trashing that Catacomb. Correct?
If so, my doubt is in Priest's "For the rest of this turn". For me that translate to "from now on (and not applicable to previous occurences)". Catacomb got trashed before Priest changing conditions. Although a trigger opens a "window" in which multiple things can happen seemingly "simultanously", the phrase in question indicates a timing, dividing before versus after. Furthermore: if Priest would not have that phrase, it would just work as said by Gendolkari. But since it have it, …