I lived in the area for a bit, and saw the high AirDNA rating for the area. 

If you do not already own your primary residence, then it will be easier for you to get a loan with low to no money down with a better rate for that then it would be for another property.

Jason shows a transfer of Deed to hold ownership.

Its just so hard in the current environment to get any cash flow with SFR (unless you bought when rates were lower or are doing a well-executed BRRRR). 

So I was thinking of a $100 increase to cover the $50 mtg rate increase plus $50 to get close to market price.

We have also had, historically, a 5%-ish difference in rent rates when renting out in December and January as opposed to other months.

They want to send me to the commercial loan department where the rates are awful, closing costs are high, and the requirements much more robust.What if I just get a second-home construction to permanent loan, wait 12-16 months for it to be built, spend another 90-120 days furnishing it, and then refinance into a traditional 30 year fixed as an investment property?

Just looking simply at rates may trap you in a way..

He is looking for $290,000 but realistic offer price with the current interest rate and other expenses is closer to $260,000. 

Others may disagree, but I would highly recommend paying off all of our debt and increasing your savings rate before investing.