It also carries a declining 5 year, 5% pre-payment penalty - Is this customary?

Although this carries risk, it is an option.

That is, they won't do any carry backs or owner financing.

Credit score mid 700, above 740.Current DTI is around 43%, credit cards utilized paid off in full monthly and I carry a LOC which I was planning to pay out but have access to when this deal popped onto my radar.

Can this be carried over to increase the losses of a future year? 

I called Home Depot and Lowe's and they both do not carry Limestone.

Outside of this, each homeowner carries insurance on their individual unit for 100% of its value as well.

Was thinking low down payment owner carry purchase of the 50% interest just to lock it up.

I used Carrie Johnston from Approved Mortgage here in Lafayette.

One company owns everything and does nothing (this is your SLLC a/k/a “asset holding company”) and a completely separate company handles all of your operations (this is a traditional LLC a/k/a “operating company”) For the operating company which serves as your face to the world and through which you do all your business, you establish a Traditional LLC to carry out the operations of your investments.