Obviously I could use the money to buy more more more, but there's something attractive about owning the rentals outright, then saving the additional cash flow to get the next one and so on. 

The house is used as an STR (we just went live) - built in 1928, remodeled with addition in 2018.

Last piece of advice is to raise additional capital because shortages while building ground up can be a painful proposition.

I've been advised by a local investor to look off market and utilize seller financing as I don't have much capital to work with nor the 2 years of employment records needed for a bank loan.

Becoming an employer adds a whole different layer of rules/taxes etc in addition to that it might not be permitted by the Broker

Additional question, the owner's property manager has agreed to deliver the 30-day notice in-person as we have not yet closed.

In my research, default rates are pretty high amongst 401ks loans. 5) If you leave your employer and want to rollover your remaining balance to an IRA to be able to invest in real estate, known as a self-directed IRA, you have to either A) Payoff the loan first, or B) When you rollover funds, the loan balance will be immediately distributed to you, thus taxes and penalties, and you forfeit all that tax-advantaged money back in the account. 6) 401ks are generally covered under federal ERISA rules, which affords you additional creditor protections, from outside of the 401k judgments.

You can also write it off as a business expense and there could be additional tax benefits for energy efficient home improvements.  

Since refinancing and investment income (like rental income) usually aren’t seen as earned income, it likely won’t affect your mom’s survivors' benefits.However, if your mom’s survivors' benefits are based on disability (SSDI), then additional financial or property assets could trigger a review, so you might want to consult a CPA or financial advisor to be sure there are no unintended consequences.This isn't legal advice.

Anything that actually comes into our possession goes into our tithe calculation.In addition to tithing, we try to give to charitable causes when we can, but we don't do it as often as I would like.