I had not thought of that, but it does make sense.
Override. Well, sensors add, and in cases where base is replaced by something worse, adds. Otherwise, replace.
Yes, they do, although it's not showing in the free cubage. The increase in size represents how much bigger the weapons are.
Short answer yes, longer answer is yes because of in character reasons in regards to ownership.
Replace on a 1 to 1 basis. Marine Country is all of the stuff that can be reasonably and necessarily aboard. Gym, sick bays, offices, barracks, commissary, powered armor vault, drop shuttles, etc. Hospital is representative of all of the space for a planetary quality sized hospital facilities that exceed standard military sickbay, additional microcompensators, etc. For cryo, it's also inclusive of prep and revival facilities beyond military minimum, the appropriate fluids and equipment, etc. For the sake of simplicity, I'm just going to say that it's just about equivalent in space and mass that it's even exchange.
You can call it Prison Space if you like, too.
In the late stages, probably. Once a ship loses most of its fighting capacity, what little damage it can do won't be enough to stop an oncoming enemy with higher HP and overtake. It's certainly a feat in piloting and needle threading, though, and mildly risky considering that the victims might not be quite as disarmed as you think they are. (It'd be a pointless gesture given the ability of the other ship to reduce it to its component atoms in response, but it can happen.) After the combat? Absolutely, if you hope to salvage anything.
Btw: Wing Captain means that when there is an established wing, Captain bonus applies to wing. Individual pilots apply XO bonus.