We cleaned the house, painted the exterior, fixed the evap cooler, and fixed the plumbing issues in the bathroom. 

Seems like a better option: no plumbing, not much repair costs, no evictions, easier screening process, no electrical generally, etc.Opinions on starting with one as first property? 

Bought a Triplex with previous fire (but not structural) damage. 2 units previously renovated and rented out by flipper. 3rd unit in need of complete renovation (demo, electrical and rough in plumbing completed but needs insulation, drywall, the works).Bought long distance during the 'Rona virus, list price was 400k, bought for 375k plus seller credit of 22,500 to put into repairs.

This job will consist of plumbing, electrical, drywall, paint, and of course a day or two of demo. 

I definitely wouldn't target any HGTV style rehabs with structural problems or even plumbing or electric that needs updated. 

And quite frequently we are doing near guts these days, with all new and permitted electrical, plumbing, cabinets, counters, flooring, etc.  

Who can help me identify the plumbing and perform full installation?

Flooring, plumbing, new roof, added a garage, new counter top in the kitchen, full bathroom rehab including toilet, vanity, tile, redid drywall throughout, added a new cement patio, new cement sidewalk around the home, new drainage & grading.

I had one we inherited who did maintain the building & I needed him until I got familiar with the idiosyncrasies of a run down 6500 sq ft conglomeration of 6 apartments added over 30 years & a myriad of wiring, hydronic heating & plumbing that seemed to go no-where.

My experience being a licensed plumber in NJ, I can design plumbing systems up to 3 family before a engineers license is required on plans.