If you're buying an in stock cap, it'll usually ship within a week. If it's a group buy it can take anywhere from 8-10 weeks from the pre-buy phase. If you ordered a custom cap it can take up to 4-6 weeks depending on the complexity of the keycap.
Typically any mechanical keyboard. These are tested on both Cherry MX and Gateron switches (the most common switches you'll find on a board). So if you have either one of those rest assured they'll fit perfectly!
For returns within the US there's a whole page dedicated to this. View our return policy here! For international orders we don't offer returns, sorry!