I know that I could save some money by continuing to manage the property on my own, however, I have concerns about being out of state and not having eyes on the state of the home (leaks, damages, etc.) and of course, parties.

Disagree with this, you still have HVAC, turnover and roof repairs in multifamily which could just as easily wipe out your cash flow. 

I can build the A-frame for $53k in materials and the shed roof cabin for $41k.    

I would like to take a stab at this.I suspect a lot of these folks reaching out to you read BP forums.And such they like the thought of infinite returns and are OK with max leverage etc.So keep in mind BP folks are reading the BRRR books and building their Core 4 which has been coined by the folks who man the podcast and wrote a book on remote BRRR ( one of the absolute Riskiest endeavors one can take in real estate by the way).So to that extent they are reaching out to you to build the Core 4 you just happen to have all 4 of the Core under one roof.

Hi all, There's a 125 year old MF property that I have my eye on, but it needs upgrades (roofing, electrical is very old, mechanical is ad hoc, asbestos mitigation, etc.).

Purchase price: $58,000 Cash invested: $32,000 Sale price: $145,000 Total cosmetic rehab including, interior paint, exterior paint, new roof, new flooring, new tile in shower, new fixtures and painting basement.

The sill should be one solid piece as tiled sills present a potential leak point at each of the grout joints. 

Likely the roof and the HVAC/furnace will be the biggest expenses that might occur but a hot water heater here, a clogged toilet there and suddenly the bills start adding up.

List of things to fix:Clean house, Carpet replacement, Floor patch up, Interior Painting, Bathtub recaulk, water heater replacement, leak check, small dry wall cut and restore, Roof fascia repairThank you.

Purchase price: $58,000 Cash invested: $35,000 Sale price: $145,000 Total cosmetic rehab including, interior paint, exterior paint, new roof, new flooring, new tile in shower, new fixtures and painting basement.