The lender may want a certified letter from the accountant to verify this fact.Best of luck!

However, I’m wondering if I need to engage an Attorney a borrower has missed a payment and it’s time to send a Notice of Default.Must the Notice of Default (NoD) be a letter sent certified mail or would an email sent to the borrower notifying them of non-payment be considered sufficient as a Notice of Default.

Years ago I have sent yellow letters to 1,000 selected addresses in a suburb of Milwaukee.

Do all contractors or PMs give you an Additional Insured insurance letter? 

Not sure what the NY refund situation is, but the federal refund is amortized with carry over credit until used up so that you never receive a refund from the IRS greater than what you paid in for the year.

Are there any good outlines or templates for an introduction letter to the tenants, or any major points I should make sure I put in my letter?

More like Big Business, carried on the shoulders of Big Gov., who big biz long bought and paid for, for these exact times. 

If I use a licensed PM, the onus would be on the PM who would carry his own E&O insurance.Interestingly enough my employees were asked what the owner did all day.

Do they want a balloon payment at some point, or will they carry the loan forever? 

I think for at least one of mine (it's been a long time) it was just a letter that my commander had to sign, basically saying I was in the military, behaving myself, and the Air Force wasn't trying to actively kick me out.