When you sell, you are doubling the number of properties each time, doubling the PV and the CF.Doing REFI's is a linear return, with a step back (reduced CF on refi property)Doing flips is a compounded return.

Keep in mind with rates dropping on cash out refinances since they reduced the LLPA hit a cash out refinance may be a better choice over a HELOC.  

I think it is unlikely and may even add a stress factor to the tenants.  

I'd also add a vapor barrier to reduce humidity in the crawlspace. 

Your job as the leader of that business is to reduce that risk as best you can.

Speaking purely from the standpoint of you qualifying for another mortgage, you at least need to charge enough to reduce your debt burden and get your DTI ratio below say 50%. 

I'm sure there's some additional planning opportunities that would reduce your taxes.

If you want to check this logic you can reduce your mortgage interest rate to 0% and see the difference in your numbers.

Whatever you do, just be aware that "not raising rent" means you are reducing your net income every year.

FIFO accounting and are unwilling to quickly reduce pricing to match moves in the broader market.