We inspect and find a thin line of mildew around the lower perimeter of apartment and thicker in corners.

A few quick answers to your questions:Any Turnkey provider (who should be full-service, do everything in-house, from scoping props to management) should provide a post-rehab inspection, but also be cool with you getting your own independent inspection.

I have enough for a down payment for a 500k house, but it will take some time for me to find a multi at that price range and anticipate paying interest rates closer to what a hard money loan seems to be (9-11%).

There are no major work currently, but what are the regular maintenance and cost of the well/septic, such as inspection, cleaning, testing, etc?

As part of the offer contract, make sure to include a significant due-diligence period to go over all the financials, and a good property inspection from a licensed inspector. 

Basically the state will inspect all rental homes for mold, rodents ect?

I do a lot of inspections for out of areas investors in oildale. 

@Avi Garg we are selling the house for multiple reasons, mainly being to pay off our debt and also move to another nearby city to be closer to family

@Stephen HuffMy points:The OP is not even a member of the HOA (and never will be, his parents MAY become members)The OP knows there is a wet spot on the carpet the size of a dinner plateThe OP has not paid for an inspector and I would guess has no inspection report, he is relying on the word "Mold" which is passed through a seller and two agents, where a report could say "discoloration" or "Mildew".

The inspection was smoothe and showed no issues.