How can I legally force A to have an exterminator treat his unit?

The issue is the type of financing you can obtain. 1-4 units is treated the same, and being an owner-occupant can help you get favorable terms from the bank such as better interest rates or a lower down payment.

For the hold, I recommend treating it as a flip...

Banks do loan to unmarried couples, but, from what I've seen, they tend to treat them as two individuals rather than one unit.

I won't discuss CCorps as I spend very little time on that arena.I will fully agree with talk to an attorney to help to draft up the paperwork properly depending on what situation you are in and what you are trying to accomplish - a different transaction structure such as a straight asset sale could be a better choice.1) If the entity is formerly a partnership, now disregarded, rev rul 99-6 walks through the analysis that has us treat as an asset sale 2) If the entity is formerly a partnership, still a partnership, 754 gives you an avenue to agree inside and outside basis3) If the LLC was disregarded, and still disregarded, we also treat as an asset sale - the assets are treated for federal tax purposes as held directly by either party.4) entity was disregarded and now a partnership - rev ruling 99-5 provides the mechanism for what is effectively a step up.5) if it was formerly an SCorp, we can maintain SCorp status and run a 338(H)(10) transaction to achieve a step up in basis in the underlying assets.

And I think that knowing U.S. law, including as imparted through Nolo Press, will help you to be fair, & even-handed in dealing with tenants, which is important, due to many people will treat you back, the way you treat them.

Just randomly came across this, might be too late @Ronak Patel but if your title and legal description says you own two lots you might NOT need to subdivide it; it's already done for you.ADU you can get it permitted and built quicker, but I don't think it'll add to the exit value as much since most appraisers and market resale is not treating it at the same dollar per sqft as regular SFH (but it's pretty close in some markets I've seen like in Long Beach).4,000sf lot is still manageable.

because after the markets treating me good I decided to come back to real estate, the issue I'm having is finding a good realtor even when I was wholesaling it was impossible to find a decent realtor.

See if you can find a lender that will treat it as commercial for lending purposes. 

Treat your new house purchase like an investment property.