This is a trickier situation than Jan Maxwell's back in 2010 because Jan had one performance eligible in each of the categories, as you said (it was for "The Royal Family" and "Lend Me a Tenor," not "Follies" though).
The fact that "Drive" runs through the spring and therefore coincides with Tony season elevates Parker's chances of a nod for that performance. Reviews for her performance in "Sound Inside" were excellent, though, with Jesse Green in the Times saying that it's her at her career best (including that earlier bow in "Drive"
which complicates things. Worst case scenario is that the contingent of the Tony nominating committee that wants to vote for Parker is divided on which is the better performance and she gets in for neither, though I think that is unlikely. I think it's unlikely she gets in for both, too, unless the % is close enough that the category expands to six slots as it did this year.