Kalaghan

1,2&5 What Lairpie said.
3 It's going to depend on your intellect too, so it varies. Which also means that fight length and maximum mana are a factor, so it's not just a question of straight regen. As a general rule though, I always ask for kings over wisdom.
4 Probably not, since int not spirit caps innervates utility for most druids and 5spirit will generally not increase your mp5 inside the 5sr by 4. I'd recommend Boar's Speed over either.
6 I'm a big fan of having a haste set and a max heal set (though haste still has some value in the max heal set). You've matched some socket bonuses that I would definitely not have (really only worth going for +heal socket bonuses imo), boot enchant as mentioned, and I'd definitely recommend the alchemy trinket over EotM.

And as for overwriting rejuvs, in addition to the scripted effects (silences, swiftmend fodder before big dmg, if you know you won't be able to go back to them for awhile), it's also required if you are total avoidance tanking and thus need to keep up 2-piece moonglade.