Hi JG19_Leaf welcome mate.
Point A: sorry cannot help there..I'm still on Win 7,but that leads to point B.
Point B: Yes I believe that all support for OFF p3 has been dropped,OBD are only a small team and to support OFF and WOFF would possibly be to much to handle.
Point C: Wow..if you've never flown WOFF from even v1 your in for a pleasant surprise.
WOFF is miles and miles ahead of OFF P3 ( I flew a lot of P3 with HITR) ..worth the investment ? I'd say absolutely 100% without any shadow of a doubt. You've probably come in at the right time mate..WOFF UE now has WOFF v1,2+3 it has all the currant addons,it's got a brilliant modding scene behind it and of course..OBD,S second to none support..it's different in every way to OFF,it has full landing patterns for every craft ( remember how your wingmen etc used to just fly away instead of landing in OFF? )
Lit airfields( drums ) for dawn/dusk/ night time missions...80 yes 80 flyable craft,full shadows with Ankors incredible shaders. A massive amount of skins for aircraft,the best A.I in any flight sim I've ever played...I could go on and on there,s absolutely loads of new content compared to OFF,watch some vids pal and read all the features that WOFF UE has. I loved OFF P3,I didn't think it'd ever be topped,WOFF UE smashes it in every way. I think there's a 25% discount on still,buy it pal,you won't be disappointed