1 sadly no
2 yes, with the tiny compass you mentioned, and also with the slide-out compass in GWX, setting a course by degrees is something I do a lot when intercepting a lone target when I don't wnt to redraw my plotted course
3 No, GWX will not make the deckgun work any differently in that regard, it will just make it a lot less accurate when fired by the crew, especially at longer ranges
as for the lock trick, that still works and I've used it at times to find out what a convoy I'm stalking is doing
as for the planes, ah yes they become a right menace until you can get the twin rapid fire 37mm for your boat, which equals the odds a little, until you run out of ammo or get a well-aimed banger down your snorkel
basically GWX will ensure you and your crew will live in even more interesting times
