I recently bought a 4 bedroom/2 full bathroom row home in the Overbook area 2 blocks from Saint Joes University in Philly, PA, with a full finished basement with a third full bathroom plus garage on this level. I am planning on renting the 4/2 on the upper two levels and living in the basement. I am debating turning the oversized garage plus a little of the other finished space into 2 bedrooms (walkout basement/garage so both would have windows), or leaving it unfinished as a garage. There is enough space either way for me to live so not worried about the livability, more considering what will be worth more when I go to sell the property in 5-15 years. I am very handy and would do the garage -> 2 bedroom conversion myself and would cost maybe $5-10k, obviously keeping garage as is would be free. Parking is also pretty easy on the street and the driveway has 2 parking spaces.

House technically is all attached so when I sell it could also leave it separated as two units (illegal, but with variance is allowed in zoning if I put the hassle in), or open it up and make it all one unit again. I plan to leave the staircase, just adding a wall to separate that could be easily removed. So house in the end could be: duplex (4/2 + 2/1), duplex (4/2 + Studio with garage), single residence 6/3 without garage, or single residence 4/3 with garage. I am trying to decide which would make the most financial sense. Thoughts or things I might not be considering? 

Thanks in advance!!