If you are using rental income and you already filled your taxes with those rental properties then they will use the your tax returns and schedule E to calculate your income.

I’m currently living here with a roommate and have a 3.3% interest rate loan on 300k and still owe about 280k.

Essex and Hudson county are blue (high property taxes too) and I would never buy there. 

I know the cash flow is weak, if not potentially negative, once insurance and taxes are included and that may immediately make it a bad deal for some investors.

Here's why.People are drawn to our area due to the absence of natural disasters, low property taxes, home prices close to the national median, and a thriving tech and research hub, coupled with the life sciences sector.Considering the ongoing influx of people and the likely rate adjustments announced by the Fed for later in this year, we anticipate prices actually  rising as buyers enter the market.

The idea is to get is much out as low of tax rate as possible.

I am confident I can find a buyer for the unwanted property but I want to make sure I am reducing my tax burden as much as possible.

Tax rates are very high level, so you will want to adjust that as you pick a more specific location to model out.  

They owe $218k on 2nd mortgage.

Additionally, for rate-term refinances, many DSCR lenders have no seasoning requirements at all.Easier qualification: DSCR lenders have much lighter qualification requirements than conventional or portfolio lenders, such as no DTI, income verification, or tax return hurdles that can slow down or disqualify loansFlexibility: While conventional and bank lenders are heavily regulated and follow standardized rules, DSCR lenders have much more flexibility and control over their guidelines.