I have a good amount in savings, and as a first-time homebuyer, I believe I can lock in a low interest rate.

Depends on really what you are looking for:-Speed - some HMLS can go "no appraisal" so can close very quickly and beat cash offers if you are in a competitive market to buy-Interest Rates - can range anywhere from around 8% to 13% (same with "points") but not usually as huge of a concern for flippers since the terms are so short-Leverage - depending on your risk appetite / capital - this is also a top concern for some (almost always over and above rates/fees) can see anywhere from around 80% LTC to even mid 90s LTC (including 100% of rehab budget)

I had a few tenants e-sign 6 documents with multiple pages in a couple minutes and realized they did not read any of it! 

My late wife and I held joint interests in a piece of real estate in our separate individual self directed 401k accounts.

Leave credit cards at home in the freezer in a bag filled with water that has frozen over....lolAmazes me how many people fall for these types of programs.When I buy NNN properties either my buyers wanting to own direct and I find the property or whether they are accredited LP investor on my syndication deals they learn with me while they INVEST CAPITAL to own fully themselves or a piece of the deal. 

And wouldn't anything agreed to in schedule B override the original agreement (like it usually does in a purchase contract)?

I know this may not seem possible, and probably not the answer you were looking for, but it would be worth partnering with another active investor, bringing in a passive investor(s), or even waiting until you have enough capital to deploy into the right deal. 

We just put them in a folder by address and date. 

Both companies are fully integrated.We are in a dozen southeast markets, and I was surprised to read your comment about investing in NW Arkansas. 

One mistake or big unexpected expense could ruin you if you only have one or two rentals that are not cash flowing.That said, especially in the current environment, if you are coming from a very strong financial position then there may be times where it may fit your goals to invest in a highly appreciating area with no or negative cash flow.