Gotta be realistic. I train in MMA and boxing and I would still be very hesitant to go against these guys. Their much bigger and just from brute force they're stronger. Sometimes skill doesn't make up for it.
Thats kinda racist. Well, kind of in a praising way,, but you are making it seem like all black guys are fighters. Anyway. Id say a strong man can take diwn a smaller average fighter women even if he is rather inexperienced. But krav maga is not just martial art. Krav maga is downright murder!! 4 inexperienced guys would be wrecked by 4 krav maga trained females.
The women would win. They'd start talking about feminism and how they think they get paid less than men, they'll complain about everything in their relationship, then the men will kill themselves and it'll be over.