Oooph that's a tough one dude, reminds me of my predicament with schools, no easy answer.
-60k is a big money difference, hmmm.
-I personally don't put much stock into PD rankings, it's pretty clear when a school is T5, T20, T50, and not, and in this case neither are, so I think that should not be a huge factor, I think neither school's ranking will help or hurt you.
-STEP 1 after year 3 is VERY concerning!! Wtf. I mean, a small hidden bonus would be that you are basically guaranteed for it to be P/F as opposed to other people who "might" still have a score following year 2. But it sound awful taking STEP 1, then STEP 2, all while putting together your app and going to interviews.
-No home programs at FIU sucks in case of the whole P/F dilemma.
Personally, I think:
If you are going full gunner mode and REALLY are going to make Ortho ****ing happen at all costs, go to SLU. 60k is nothing in that case. You need those research experiences, especially at WashU.
If you think you might chill out and want primary care, or even just something less competitive than Ortho, and match somewhere in Florida, take FIU.