i would definitely say that Jiu jitsu would be best. Jiu jitsu deals with disarmament, throws, effective point strikes, and has no baring on size because it, simmilarly to aikido, uses your opponent’s size and movements against them. I’m about 5’ 8” and 145lbs, and i can just as easily throw someone who is 6’ 6” and 200 or 300 lbs as i can someone who is smaller than me. Also part of it is to practice falling properly so you dont’ get hurt if you are say….pushed down or shoved around. There are grappeling disaplines of it as well (once you get them o nthe ground with the throw you can finish them off on the ground). it’s good against multiple adversaries to because it is based around from escaping from holds others may put you in (one holds your arms and the other goes to punch you in the face). the throws do a lot of damage particularly if they aren’t thinking about it, i practice on mats in a monitored environment and i’ve still gotten hurt, minor injuries to both shoulders.
i would also recommend looking into taijutsu. it’s a martial art that is based on multiple persons attacks, and deals with linking attacks together. Basically using your momentum from each move, strike, punch, and kick you make to lead into and power your next move, strike, punch or kick. it’s very effective, and the relentless attacking really takes the wind out of the guys who are attacking’s sails.
two more things, sorry for the long response. the first if you do end up in a fight one of the keys to winning any fight is that you have to be willing to truly hurt the other person. no pulling punches or letting them go until they are subdued. if you have to fight you fight to win at all costs. the second thing is that fights should not be sought after. they should not be started, they should be in defense only. with any martial art you can kill people, and thus it should be respected as much if not more than any other weapon gun, knife, etc. good luck