If this represents a small portion of your portfolio that could be easily replace then why do it?  

They bought land, built condos, then sold those condos.

I have set up a master bank account for the holding company through Baselane, then individual bank accounts for each LLC which are sub-accounts of my Holding Company.

Multiply $898.82 by 12 months then by 15 years is only $161,787.60. 

If tenant B is leaving at the end of the month, then that threat is gone. 

Then as others have said, you may be able to use a local PM.

check your local laws and if what you have in the lease doesn't violate the laws, then do it. 

But then I got some quotes on how much local builders actually charge to build an ADU, and I balked a little. 

Then it's merged into that rehab which is an asset.

The "less" option would be to "just" fix things at around $20-30k then down the road spend about the same when its time to sell the house to make it look the best and not get the extra value that a bigger project would bring and not enjoy a nicer, fixed house until then