She had a valid lease and was on time.

Rental income, after allowable deductions, is taxable as ordinary income.Business Licenses and Fees: In BBL, you'll need a valid business license to operate an STR.

My question is the old POS report that expired was valid for one year.

If after adding the additional monthly recurring costs (electricity, gas, water, internet, insurance, lawn care, snow plowing, etc.) to the standard long-term costs (Mortgage, taxes, regular insurance, etc.) the property won't net at least $100 if I can get the average rent I see on FF for that area, then the property isn't worth more investigation.

On top of that, my company provides a vehicle, gas card, and I am paid from the moment I dispatch my home. 

Of course, your opinion is just as valid as mine, and if it works for you, that's all well and good.True, you definitely do NOT want to give up a 3% loan....BUT there are numerous CREATIVE ways to build net worth FASTER than hold and reinvest cash flow.  

My lease says that the lease is not valid unless the deposit and rent is paid.

Separately metered gas & electric are generally viewed as more valuable because water is less commonly metered.

That is a very valid point.

Few more points:Their lease is valid till May 2025.This is the first time she even told me about mold.In the email she did ask me to settle the lease.I have a little less than a month of rent as security deposit, which I am ready to settle without any additional penalties for abandoning the property.At this point I am okay with her leaving the place, just I want to get the control of the property back to fix the mold issue.History:1) Recently the AC has been replaced and after that there was some intermittent issue with the installation (temp doesn’t reach target intermittently) and I had to call the tech back 5 times to finally get it resolved.2) Also last month I replaced electric range with Brand new Electric range.3) Two months back she said the refrigerator was leaking, I asked her to send picture of the make and mode of the refrigerator, but I never got a reply back.4) Also for last 4-5 months she has been asking me to send her 5-day notice so that she can claim reimbursement, I was sharing a document and she was paying the rent a little late.