No. Desk charging is about giving the back of the phone a clean, flat connection with the charger. The strap does not need to be removed just because you are charging; simply make sure any detachable storage is not sitting between the case and the charging surface.
Yes. The wallet is detachable, which makes desk charging easier when you want a lighter setup.
Yes, as long as the MagSafe-compatible case can meet the charger surface directly. Because desk chargers vary in shape and angle, adjust the phone slightly if it does not settle evenly on the first try.
The detachable wallet is listed as holding 4-6 cards and includes RFID-blocking protection. The fit can feel different with thick cards, embossed numbers, metal cards, or folded cash. If you like a slimmer profile, start with fewer cards and add only what you truly reach for during the day.