Okay, I just have to get it off my chest that having Ranma be the one who gets pregnant with Saffron makes no damn sense, given he was never female while in Saffron's presence, not to mention that the base idea is seriously overused and it boils down to pissing on Ranma just for the sake of keeping Akane out of serious trouble, which is cliche and overdone even in the original series.
Anyway, who said the Joketsuzoku, Musk, etc would want to conquer the Phoenix People for their territory in the first place? Nobody suggested that, as far as I'm aware - the only reason I suggested that the Musk & Joketsuzoku might declare war on the Phoenix is because the Byankala people are all aggressive assholes and the Phoenix People are now weak and disorientated with the loss of their leader. It's basic human nature. Even then, I stated that it was far more likely that champions of the Joketsuzoku, Musk and any other obscure martial arts villages in the region would focus on coming to Nerima to either challenge Ranma in order to prove their own badass credentials or to try and seduce him (not neccessarily literally) into becoming an ally.
Community at large, to be honest, is going to look down on Akane. Japan is a society in which public face is worth more than your life, and Akane is unmarried and a pregnant teenager, an extreme scandal. If she can't get Saffron aborted, then sending her out of town so nobody realises that she's pregnant or sees her having the baby in order to try and diminish the scandal would be the most real-world thing to have happen. Quietly ignoring her and regarding her as persona non grata is still the least Akane should expect if she remains around her community and doesn't get somebody to marry her and convey some semblance of respectability on her. So long as she's married, it's alright if she's pregnant, though people are still going to think less of her for getting pregnant before the ceremony.
True friends will subtly support Akane as much as they can, despite public disapproval. Even then, they'll need to take it down low in order to avoid being ostracized themselves, though extremely good friends would probably try and shame others for this attitude. After all, this isn't Akane's fault and they would join her in placing the blame on whoever impregnated her.
Falser friends or friends with weak wills would join the general crowd in ostracizing Akane.
Rivals, if they believe Akane is pregnant with Ranma's baby, will be homicidal, though you could establish sympathy for them by having them give up in despair, declaring that there's no point denying it any more. Honestly, I could see Kodachi doing the latter most easily, given she makes it clear she just chases Ranma because she thinks it's fun and he's sexy. She could walk away any time she felt like it. If/when they discover the baby isn't Ranma's, though, they're likely to mock and jeer her for her hypocrisy or be irritated that she kept stringing him along like that if she was seeing someone else on the side. They would certainly try and get closer to Ranma after that, seeing the divide forming between him and Akane.
If Akane would find out about P-chan being Ryoga before trying to abort... honestly, that's up to you. Normally, Ranma does try and make some effort towards hiding it, but this time, Ranma would quite likely assume that Akane already knows the truth and would probably make no bones about accusing him of knowing her pet was really a transformed human all along. And if she does learn Ryoga is P-chan, then all likelihood is she would accuse him of being the father. She knows she hasn't consciously had sex with anyone, but she is willing to believe Ranma is capable of rape, and learning Ryoga has been sneaking into her bed by pretending to be a pig would make him look just as suspicious as Ranma has looked in the past.
As for Nodoka... well, there are really four sides I can see her "joining".
Ranma's Side: She believes Ranma when he swears he isn't the father and turns against Akane for being a dishonorable adultress. She would probably support either transferring the engagement to Nabiki/Kasumi or breaking the Tendo arrangement all together, given that they have "proven to be totally void of honor".
Soun & Genma's Side: She believes Ranma is the father of Akane's baby and so demands he restore her honor and his by wedding her.
Akane's Side: She believes Ranma is not the father of Akane's baby but that it is not Akane's fault, and so turns on Ranma, demanding he either be cast from the family or commit seppuku for being so unmanly that he either forced his future wife to turn to the arms of another or allowed her to be raped.
Her Side: She believes Ranma is not the father of Akane's baby, but it is her fault she got pregnant, disowning or executing her son and breaking off all contact with such a dishonorable, uncontrolled family as the Tendos.
In all honesty, this story is, at best, going to be very bittersweet. Emphasis on the bitter. Writing this is going to catch a lot of flak.