Hi, I have a few suggestions for you, and i'll reply to your questions.
1) I would try an earlier nap, 12 like you say and ssee what happens.
2) Let her play in her cribif she is happy. She will get tired and falls asleep eventually. My son would sometimes play for up to an hour before going to sleep. I just left him.
3) Do not go in or respond when she calls for you.
4) If she throws the toys over i would go in 1 time and replace them and say if you throw the toys out again, mommy won't be baack to put them in.. something like that. My son would do the same, but wouldn't sleep cause he'd be distressed baout the toys over the edge. He soon learned that if he threw them after the one timei'd put them back, then they were gone. he stopped throwing them.
5) no. I think that gives her the attention for screaming and having a fit, so she's getting what she wants.... but i dont' know what else i'd do!!
sorry if i'm not much help