3 vs 3 battle- Morals off and a fight to the death- Takes place in a completely empty Times Square- No prep, random encounter- Batgirl is Barbara Gordon. Angel is NOT Archangel.
I'll go with Beast, Angel and Black Widow. Beast could take Batman quite easily in my opinion and then Black Widow has Black Canary. However I think Batgirl could beat Angel, although Beast and Widow could join forces to take down Batgirl.
Beast is the superior here in terms of physical stats, and by no small margin. He's trained with Banshee and has dealt with sonic attacks before, it's nothing new for him. Plus there is Angel and Black Widow, who are very competent fighters themselves.
Beast could easily take Bats and Batgirl himself while Angel and Black Widow take out Black Canary if needed, or Beast can take on Black Canary while the other two keep Batman and Batgirl busy.
Thanks for reading,