You will likely need to redo every door jam and all trim as sheet rock is considerably thinner than plaster and lathe.

The home has decay on the corner trim on the roof, shingles are near the end of their service life, leak in furnace, and some pretty bad electrical issues.

There is a similar duo in my market that I've gotten to work alongside a few times and the arrangement I see with them is that the GC does everything at cost and the partners share the profits (50/50 for them, but whatever makes sense for you guys consider risk exposure and buy-in).A word of caution . . . as I'm sure you know trim carpentry (and any subcontracting trade) IS NOT general contracting and effective labor management. 

But that's your personal decision, if you like the high cashflow with low COC.I would look at if rents can be increased or how much it would cost to put some vinyl floors, white walls, and black trim or whatever it may need to be more optical to premium rent.

The issue, other than the cost of drywall is that the OSB is flush with trim/windows so even 1/4” drywall will look terrible.Anyone seen this before?

There will be basic maintenance on the outside with cosmetics on the inside (drywall, paint, installation of cabinets, trim, etc.). 

To avoid moisture issues I usually clad the upper shower stall & trim it out with cedar.

Also look carefully for any area where the animal may have been kept during the day which may have flooring/trim that has been saturated in urine.  

As our skills improved we moved on to window and trim painting, then eventually to use the rollers on the walls. 

Painting window trim $250 each?