The new property was used as a rental for about 6 months, but circumstances changed and I ended up making it my primary for the last 1 yr and 9 months.  

If you're thinking about changing the use of a property due to extenuating circumstances (family dynamics, loss of income, COVID, recession, etc), then it's probably a good idea to log that thought or share that with someone in a durable format. 

It's not necessarily from Tenant neglect and you would be hard-pressed to prove that in court since you weren't around or involved at the time. 2.

If you can prove that prices have increased to that extent and show that the appraiser neglected to include that valuable information, then you have substantial ammunition to have a revision made.

Our decision completely depends on the applicant and circumstances (why they want to do advance rent).

This is a business decision so it looks like you're free to make the best decision for your given circumstance.

Even if the cash flow isn't able to change your immediate circumstances it allows for you to continue investing in real estate.

But if so your extenuating circumstances are very compelling.  

In some circumstances, vacancy is unavoidable because time is needed to prepare the unit. 

I'm not a tax professional, and I don't know your entire tax situation, but I'd recommend you consult someone who is and can offer advice specific to your circumstances.