1. Yes, apart from Lolonee the event plats have the same skill both before and after CC so you can use them whenever for CR/SU.

2. Nope, never. Unless you count the "packages." They are onetime deals of which we have one so far. There is one more on DMM that we haven't gotten yet. Aside from that there are never any actual sales. There also is a black ticket where you can pick a black, but it is a onetime thing once you reach level 10 on DMM. It has yet to reach nutaku. But all in all, no you won't see sales for SC or guaranteed blacks for nutaku gold.

3. Every 1½ months ish i believe.