Wow, thanks everyone. This thread really took off and there are some great thoughts/tips offered.
Something I didn't know about passionfruit is that it's quite sour on its own, so what I've decided to do is try this variety a few times, trying a new variation each time. Batch 1 I'm going with lime juice/passionfruit at 0 min, and then adding again once fermentation is complete.
If that doesn't add a decent punch (I suspect it won't), I'm going to experiment with sour mash and 88% Lactic Acid to learn more about those methods. At worst, I get some experience that I can use when experimenting in the future.
I bought some Goya Passionfruit pulp from the grocery's freezer section and took a taste. Boy is it tart!