Even if you buy in an LLC, it takes like five seconds to find out who the principal is.

Another advantage for a landlord with capital gains (or anyone else) is that the IRS views receiving the principal over time as an installment sale which can avoid a large one-time tax hit and being pushed into a higher bracket in a single year.

If I pay it off I immediately get 900 / m cash flow from principal and interest no longer going out the door.

This does not apply to prepayment of principal by you as the owners or if sold or if refinanced by the bank.· Collateral will be a 1st lien mortgage and GBSA on the real estate and personal property being purchased, respectively.

If so, you might consider setting up an installment sale from them to you, where the annual principal and interest payments are under the annual gift tax exclusion (which is fairly high if the “us” in your comment means that two or more of you will take title).   

I also don't feel the need to buy many doors or larger buildings; my personal goal is the most revenue, equity, principal with the least amount of tenants.

Quick numbers:Purchased at $237k, currently valued roughly at $266k, I have $144K left on the mortgage at 3.976% (principal payment is ~$350/month), current rent is $1800, net cash flow is $245/month.This is a townhouse that was built in 2012, and nothing of note has needed replacement.I'm confident that I could easily get a new tenant in for $1800-2000, but I believe that maintenance cycles will be coming due in the near future. 

Non-Payment of Principal or Interest.

I am not sure which documents are needed in order for her to only be taxed on the interest she receives and not the principal payback.

In the event of you wanting to sell your home, it is important to know what tax deductions will get you the most out of your sale.When selling your home, you can deduct:-Selling costs, as long as they are directly related to the sell of the home and it is a principal residence,-Home improvements and repairs within the last 90 days of closing, and-Property taxes up to $10,000