Washer/dryers are often abused, so there's the initial cost of purchase and the risk of increased repairs.

Its a standard excel model that can be found with a little googling.

After completing renovations, the estimated appraised value has increased to $370,000.

That may increase your cost or limit the coverage you can get.The Year that the following were updated (either partially or fully) would be good to know:- Heating systems- Roof- Plumbing- electricalSome companies will not write properties with systems that have not been updated.As long as you are living there, the proper policy for a 1-4 family is a "Homeowners" policy.

Why not just save for the downpayment and work on increasing income to qualify for a traditional loan?

Just make sure you are saving towards those slow months during the peak months, buy a deal at the right price (don't overpay just because its a turnkey STR or you think it will make more money than projected), and look into ways to increase bookings during those slow months with some marketing and operation tweaks. 

Did lenders reactivate HELOCs after the rates increased?

Materials have increased more than 20% in the last 5-8 years.

But once I got the bills, I increased the rent with the tenant's approval and signed an addendum to the lease stating the rent increase would be X and the owner would take over utilities.

Because here, the proposal would increase property taxes about 5x.