I think you're looking at the problem all wrong. The question is not whether she is the right co-founder to present to PG, JL, etc., for the sake of applying to YC. Instead, you should be asking yourself if she is the right person to be building a company with. A startup is essentially a shotgun marriage where the company is the baby. Can you see he being the right person to bring a company into this world? If the answer is "yes" then start working with her. Whatever you do, don't base your decision on what YC is or is not looking for. They look for teams that have qualities that suggest success and that are aligned with their investment thesis. If you have a team that doesn't fit into their investment thesis, but is the right team, then that's all that matters.