Attic conversion worth it?

[Weston Young]

Debating on whether finishing the slopedattic of my recently purchased buy and hold triplex is worth it. The attached images show the attic's current condition.

The room in the back is insulated and and would require finished flooring, heat, & paint (62 sqft above 7 ft height).  For it to be considered a legal (4th) bedroom it must be 70 sq ft/ have fire escape so im thinking it would be better to list it on the lease as office/storage space. 

Other slightly larger section of the attic is completely unfinished. Seems renovating this part of the attic would require ceiling insulation, drywall, flooring, electrical outlets, & heating source.

My concern is that a reappraisal wouldn't add anything to legal square footage. Any insight on whether the ROI would be worth it or other considerations I am missing would be much appreciated.