I know, but I'm bad at that. As for spells required to make them, I'm probably going to cope out and go with "only Parun (highest ranking member) of the guilds can make guild charms".
Not really. A TWF may wish to use the throat version, especially if he doesn't have an amulet of constitution yet, and certain casters are likely not going to be able to use the slotless version.
That's true, but it will mess the flow of things up, since using an immediate action on your turn disbars you from using a swift action on your next turn, which I feel creates wierd affects. Basically I'd prefer not to make the activation of something an immediate action if it can function as a swift action.
No, I'll add that.
I'd rather keep them all as the same time, and note down the alternate concept of a charm for something more independant fluff-wise. Feel free to post your version in its own thread to see what people think of the idea. Personally I think its rather good, certainly more mechanically elegant than what I came up with, and even if 4k is judged to be too much for a 1 shot item for the PC to buy for themselves, it should make an interesting treasure drop.