There is no provision in the game for borrowing money from the bank. Given that the UK would need 10 IPP in hand (whether their own money or an Allies money) in order to have the ability to declare war on a minor power. Doing it the other way would be like buying a tank on your purchase units phase and then paying for it on your collect income phase.
Militia have changed a bit in V-3. You can build as many militia in a territory as the territory is worth. So if the territory is worth 3 you can build 3 militia there per turn. You can also build them if there is no point value but you are limited to building one militia. You can only build one militia in a captured territory no matter how much the territory is worth. You have to own a territory at the beginning of your turn in order to build a militia there at the end of your turn.
On a side note, I have seen the expansion set for the Chinese Civil War. It is awesome. I thought ho-hum when it was sent to me but when I looked I was really impressed. I was always bored with China but I can see it being a big improvement in the game. Sorry but I can’t give you any details, you’ll just have to wait until it comes out.