My credit is poor right now but can easily be improved as my income is much better lately. 

Refinancing next year would likely allow you to lock in a potentially lower rate than the 8% you're currently at, especially if the market conditions continue to favor lower rates.Avoid Duplicate Fees: You're right in thinking about avoiding duplicate fees for the refinance and HELOC.

Others tap into personal savings or use business lines of credit for more flexibility.

You're the fish.They often use a mix of fear, threat and urgency to push a target to act.It can be as simple as a 24 hours sale from your favorite shop that requires you to log in to your account first or your boss asking you to wire money right now or he/she/they will lose an important contract that will cost millions.So cybersecurity is important because without that, you might have an incident that can cost a lot of money, impact your reputation and might affect your credit score.

I think they are just an extremely conservative bank and that is their interpretation of Fannie's guidelines.I have already gotten approved from some other banks (credit unions), so I'm not worried, but I am curious if anyone else has run into a bank telling them they need at least a 20% down payment on 3-4 units, regardless of it being FHA or not.

I don't charge security deposit or move in fee nor do I care about credit. 

They do free sign up with 100 free credits so you can try them out.

The more lead credits you purchase at once the more you save.

This access allows them to match investors with the most appropriate lenders, often resulting in favorable loan terms that align with the investor’s financial capabilities and project timelines.Moreover, a skilled private money broker excels in navigating the complexities of securing financing.

Knoxville has some good ones like First Tennessee, Pinnacle Financial Partners, Y-12 Federal Credit Union.