We currently occupy the business space on the bottom paying $3650/month for about 10 years now.

This is an important tool for anyone buying a tenant-occupied property.

If you're going to owner-occupy your first investment (aka Househack), NY has plenty of options in the outer boroughs - mainly Brooklyn, Queens and the Bronx. 

Right now I am in the middle of investing a multi-family home or potentially or Condo/apartment in Sarasota, FL and airbnb the other rooms that are not occupied.

They have all your money and are occupying your property.

At this point I would like to sell it, and my realtor is saying that it’s marketable only to investors since owners/occupiers will not be able to get a conventional mortgage (and the insurance will be prohibitive).Is that true?

Recently I applied for pre-approval in order to start looking for small multi-family units to do an owner occupied house hack, I was, unfortunately, denied pre-approval due to my low income.So I had an idea and I was wondering if this is 1) Legal/Feasible 2) Effective/Smart or Not.

At this point I would like to sell it, and my realtor is saying that it’s marketable only to investors since owners/occupiers will not be able to get a conventional mortgage (and the insurance will be prohibitive).Is that true?

I would also request Estoppel agreements from the current tenants to verify that the $550/month lease amounts are accurate.Aside for the numbers, it seems like a good owner occupied 4-plex to get into, but I wouldn't bank on pocketing the difference between the rental income and the $810/month.

If you are looking for a conforming residential loan, your only non-owner occupied option is the "investment" conventional loan at 20% to 25% down.