Explain in the letter that legal action will be taken to reclaim the amount they owe. 

Wholesaling is legal.

Corporations are considered separate legal entities, so the dealer status does not pass through to you as an individual.The other issue to consider is self-employment taxes. 

Trying to evict the tenant, but not sure what loopholes are available or if we should seek legal help! 

Nothing outside of apartment communities zoned MF in beachwood, but there is still a way to rent out a "room" legally in beachwood, and you don't have to do a yearly rental inspection ($500 annually!). 

It really depends.You also have to know if local zoning even allows an additional ADU and if so, can it be legally rented.

It is more of a legal question and I am not a lawyer, but from my experience, it doesn't really matter in which state you create an LLC since you will have to register your LLC in both states anyway.

Then if he needs additional materials he needs to submit a change order or he forfeits legal claim to any more money.

Because of my age, I may not legally sign a purchase and sales agreement (required to wholesale), I am about to go to college which I am completely undecided in and about to completely switch markets.

I have also built up a cash buyers list of around 600 and have all of the legal documents.