Would houses with this kind of cooling system be able to attract high quality tenant?

Once you see your savings rate consistently increasing, go for your Heloc idea to buy a property.

If i refi or heloc and my fixed cost increases 300.00 per month, I’m still clearing 700.00 per month.

Then when it comes to financing this is where you can increase your offer slightly if its owner financing because he can provide cheaper financing than a bank and he will ultimately make more because he is getting interest on a loan.When he asks "why do you get a profi"t you mention that you are taking on the risk of fixing up the property. 

From listings, it seems  properties now in Union city/Weehawken are increasing faster than those in Jersey City areas. 

Like residential tenants, commercial tenants don't want a big increase in their rent.

The one specific one sits 40% vacant and we will be adding additional tenants to increase income.

But taking my willingness to move on as weakness and incrementally increasing the bill amount unreasonably.So, I want to prepare myself for all eventualities.

There is no other investment vehicle that increases net worth and throws off cash quite like real estate. 

You could also simply give notice that at the end of their lease the rent will be increased by $1,000, which would probably have them move out anyway at the end of their lease.