First questions: Yes and Yes.
Embrace: Drowning behaves differently if you are underwater or not. That's the only thing it's referring to.
Ability damage: I'm honestly not sure, and given how high the effect multiplier can go, it's possible to one-shot pretty much anything that fails the save by the end of the game. I think I'll drop most of the ability damage ones down to 1 per multiplier.
Run with the Pack: No, it doesn't. That's why it's immediate and not on the target's turn.
Misanthropic: No, has to land in a safe space. I'll grab the usual wording for that.
Thousand Years: Yes, spellsong is spellcasting. The full list is spell, psionics, incarnum, truespeak, binding, mysteries, runes, spellsong, osteomancy, necromantic, rituals, slices, spell seeds, thresholds, invocations, and probably a few more I've missed. Hence not putting it in there.
You Shook Me: It's a quote from the earthquake spell. It's not falling damage at all.
Ice Ice:
IcebergDie for the Cause: Will add a link.
Crush Em: Prefer no save damage? Or having a Fanatic? Or you need the target captured?