1, It goes at the end phase, as whilst it says it can only be used once, it does not say it last until the first time it is used. There for not specifying an end time, so it must end in the closing phase.
2, The ability's have the same result, but different names, so they should stack.
3, Spells and ability's of the same name do not stack.
---------- Post added at 07:27 PM ---------- Previous post was at 07:26 PM ----------
Sorry, just thought over what i said there, and it is all negative But as far as i understand that is how they would all work just above.