Since this property hasn't been fully converted to a multi family, you may want to run the comps as a sfr.Spitting the utilities (if they aren't separated) may not go as smoothly as you expect.A single thermostat that controls both units is probably not going to go over very well.

Does anyone have experience or knowledge about converting two vacant rent stabilized apartments into 1 large apartment. 

After 1 year you paying off the CC, this will be converted to unsecured cc and you will have your money released.We also have CC on the company name but this doesnt help with your personal credit building.Best is you get 2 or 3 lines of credit asap (credit cards, car loans, purchasing items like appliances on credit and paying of in time...this will build your credit. 

Then they my use Roth backdoor  policy to convert IRAs to Roth .

Tell us some details of the deal and your plan to increase the home's value.Any chance you can convert it to 2 full baths?

My father and I just bought a 2-Flat with hopes of turning the basement into a legal unit. It has adequate ceiling height and is very big. Has anyone had experience with this type of thing or familiar with the process?

Since they made such a mess I ended up renovating the unit and converting it from a 1bd to a 2bd and for $10k in renovations I now get an extra $3600/year in cashflow.

Is it possible to get a line of credit on a rental property  that I converted to an LLC(Massachusetts)?

The property has 4 units total: one main house (will be our primary residence), a converted garage (upstairs and downstairs unit), and a pool house.

They are both on basically the same street.Both homes have a detached garage that could be converted to liveable spaces and rented out.Home #1 is currently rented with a great tenant, basically month to month, $850 per month.Home #2, I live in, and its almost fixed up enough to rent out.