If you move into the ADU, do so prior to placing someone in the primary.  

The prior owner's agreements with the tenants are as legally binding as it would have been with your signature on it.

I have this idea floating around to build an extension on the property or a separate ADU and finance it myself prior to refinancing, but that might be a bold move this early on in my REI career. 

The house was not inherited, it was sold for a $1 to us several years prior to the resident (a family member) passing away.

view=publicIt's a 3 bed 2 bath house, almost 100 years old, and the seller made a bunch of updates to the house (fixed roofing, foundation, re-ran electrical wiring, redid flooring, and interior paint) prior to me moving in.So far, I've added a dishwasher to the place, and here are my thoughts as far as other "value adds" go, but I don't want to invest the money if you guys and gals don't think there's much opportunity for a return on it...

The prior prop mgr told me the owner lives in Japan.

For example:General-Filters (furnace, air conditioning, oven exhaust, refrigerator, and water)-Stove burner when the “eye” needs simple replacement-Batteries and remotes that service the premises-Fan and light pull strings-Smoke and carbon alarms testing and batteries-Ensuring appliances are properly plugged in, hooked up, and used-Removing dirt, debris, and lint in and from connection pipes (e.g. clothes dryer)-Tighten loose screws on all home functions (e.g. doors, hinges, handles, socket -Balancing off-balance appliances-Cable, internet, and phone jacks-Fire extinguishers-Systems operation (e.g. security, irrigation, HVAC)HVAC-Monthly A/C filter and drain line maintenance Electrical-Reset “tripped” GFI breakers-Light bulbs (throughout and at the end of the tenancy)-Blown fuses-Reset breakers in the outside and inside breaker boxes-Socket and plug outlet coversPlumbing-Unclog drains or toilets-Caulking around tubs and showers as needed-Gas pilot lighting-Leaky faucets and shower heads-Toilet flappers, handles, seats and seat lids, tank lid, and flush kit-Sink and tub stoppers-If septic tank present, use RID-X as directed on consumer box-Proper cleaning of garbage disposal-Loose faucets and sprayer heads and hoses-Faucet filters (i.e. aerator)-Open exterior plumbing clean out when necessary (e.g. sewage backup)Exterior-Routine lawn (and pool) maintenance-Adjusting sprinkler heads as necessary-On the last month of tenancy, tenant must perform required lawn maintenance no sooner than 2 days prior to vacate dateThere’s a lot to consider as a landlord.

We’re putting LVP in all our homes unless we buy something that has had the carpet replaced just prior to me purchasing it.

If it makes you feel any better, I always have to spend tens of thousands of dollars whenever I buy a new property from all the gremlins I discover (or the tenants tell me because the prior owner was a deadbeat). 

I happened to call at the right time and he sold me this property at a fair price AND allowed me to place a tenant in the property prior to closing.