I recommend David Greene's book on BRRRRing and J Scott's book on Estimating Rehab Costs if you need more guidance. 

David Greene did a great job breaking down the BRRRR strategy here.

We discovered the humidity problem from one of the tenants seeing a small amount of green mold (this is a fairly new tenant).

You are green and don't know what you don't know.It is important to get a good agent who is familiar with the area and the rules around STR's.

One of them has a green card, and the other does not.Both are in India now but used to live in the USA.Assuming I follow all the securities law and regulations, from taxes standpoint, do either one of them have any US tax liability?

I'm still pretty green to the real estate investment game, so please share some input.

Sorry for being so green about this.

I was wondering what will be the estimated cost to convert a car garage into a legal livable unit, and what will be the proper process.Also, is there restriction or law issues if I want to convert the green grass space in front of the house into a parking space?

I have read David Green's books on the BRRRR strategy investing and Long-Distance investing. 

David Greene’s book does well to describe the questions a would be investor should have for them, but I am curious about the other side.