I think Bru's gonna knock this one out of the park, myself. I can see Rikki teaming up with the 50's Cap, myself, purely due to the fact that he's probably the closest thing to the Cap of her world.
Still, I do find it curious that Bru would pick her up as a character, but, that said, the less he mentions the alternate-world and Onslaught stuff, the easier it's going to be to fit her in. As it is, it really is difficult to guess where he'll put her, really, but somehow, I just don't see her being Bucky's Bucky.