Geri,Whether or not you decide on LLC/Corp ownership or keep it in you own name, having adequate limits is your best protection. 

I also do look up any foreign addresses listed in rental or ownership history, and will contact prior landlords whether or not I speak their language.

The IRS and the courts have stated that mere co-ownership, rental, and maintenance of real property does not create a partnership for federal income tax purposes.

Since I don't have an LLC, is there any concern/ caution/ potential future issue if I transfer funds to my personal brokerage account? 

Looking at this as long term ownership and also as a second home that I will rent out via a vacation rental management company.

I've been more than willing to cooperate and draft the necessary documentation to protect their investment, but they have since changed their position/requests several times and are now demanding that I transfer all assets to them and walk away. 

How can that be transferred to a new owner?

I wish to transfer title to them to an Indiana LLC.

It is a like exchange, so you need to transfer into an investment property.

…Copies of any contracts that will transfer to buyer including laundry, trash, phone, equipment, etc.