So FSPassengers was my favorite addon for FSX. I can't find anything similar that works with P3D. I found REX Latitude, but it doesn't look like what I'm looking for really. Any suggestions?

Fscaptain. Unlike FSpax it's still actively developed & has active support. It doesn't include economy though, however I believe they are currently working on some kind of economy addon that would work together / be part of FScaptain, 

Awesome! That's exactly what I was looking for! Thank you so much