That awkward feeling when you are playing Jubilee hero and the game instructs you to discard your hero because you defeated a side scheme. But seriously, we have three ways to rule this weird interaction (playing Jubilee as your identity and dealing with the forced Jubilee ally):
1) Jubilee ally does not enter play and is removed from the game. Since your not responsabile for her being defeated, which was the RAI, I believe she does not go to the victory display to lower the point tally.
2) Jubilee ally goes directly to your discard pile and will basically only serve as a dead discardable card when she is eventually drawn. Since your not responsabile for her being defeated, which was the RAI, I believe she does not go to the victory display to lower the point tally.
3) Pretend the scenario ally has another random name that is not Jubilee. This way, you get to use the ally just like she was designed. Maybe pretend there's a multiverse, just like some people do with the Nebula x Nebula situation.
Option 3 seems best to me, what do you think?