7 Jun 2013
A card with a splice ability can't be spliced onto itself because the spell is on the stack (and not in your hand) when you reveal the cards you want to splice onto it.
7 Jun 2013
You choose all targets for the spell after revealing cards you want to splice, including any targets required by the text of any of those cards. You may choose a different target for each instance of the word "target" on the resulting spell.
7 Jun 2013
If all of the spell's targets are illegal when the spell tries to resolve, it won't resolve and none of its effects will happen.
7 Jun 2013
You reveal all cards you intend to splice at the same time. Each individual card can be spliced only once onto any one spell.
7 Dec 2018
If the returned creature leaves the battlefield before the end step, it will remain in its current zone. It won't be exiled.