I'd ideally like something that'd be an interest-only construction-to-perm type of loan for a small multifamily like mine, with the cap-rate helping reach the proper ARV %'s that most lenders need.

I never really take it serious with rent rate optimization.

I had a similar experience also didn't get 2 of my properties rented by November after I turned over one at the beginning of August and the other mid September.I switched to another local but flat rate company who rented both in less than 2 weeks.

The purchase price, loan amount, your interest rate, whether you need mortgage insurance, your homeowner's insurance cost, property taxes, and your current monthly debt obligations all factor into your DTI.  

Here are highlights of the program right from their website:Program Benefits-A 30-year fixed interest rate mortgage loan, several rates and loan options available-Down payment assistance (DPA) 3% to 5% of the loan amount-You do not have to be a first-time homebuyer-DPA provided as a grant (never needs to be repaid) or 3-year deferred forgivable second lien loan-Available statewide through a network of participating lenders.

(Urban, suburbs, rural) What population sizes and growth rates?

The interest rate ended up at 9.3% with a 9 month term, interest only payments.

I am 35 and the owner of a 1000sqft 2 bed 1 bath starter home that I bought for 150,000k in 2020 at 2.75% interest rate. 

The most common criteria I see investors evaluating when considering location are job growth, population growth, and school systems.

Good schools are what I value most.