A Universal Time has so many different currencies because each one is tied to a different system, uCoins for quests and bosses, Universal Points and Fragments for the premium Limited Shop, and Event Points for time-limited content, rather than one currency covering everything.

Yes, you can still get Limited skins that are no longer available in-game through a shop like this one, even though they can no longer be earned through normal gameplay once their original event or window has closed.

Yes, you keep the Stands, materials, and currency included with your purchase, exactly as shown in the listing.