Our office manager argued that all the proposed repair such as drywall, floor, paints, doors, windows, thermal and moisture protection treatment, etc are part of the tenant responsibility.

I can help you ballpark your ground up builds or renovations, or ad hoc questions like "What does tile/flooring/painting cost in $/SF?". 

Taking some of that space for the bedroom would only require framing in a non-load-bearing wall, closet, and bedroom door, plus adding a few electrical outlets/switches, and then finishing with insulation, drywall, paint, and trim. 

Painted the buildings and Managed the property myself.

I’ve heard that rolling paint provides for a better looking finish over rolled.  

I've never heard of a painted driveway. 

I also explain leaving a few minor nail holes is fine, but if they patch, themselves, they will be charged the full repair if it doesn't match the wall texture, ready to paint. 

Tenant paints all walls black6.

If you go forward, make sure they handle all maintenance & repairs on the property too because these organizations typically have in-house staff..Snaking toilets, repairs, grass cut, snow removal, paint...Make sure you're covered with insurance as well. 

New flooring, new paint, new fixtures, updated kitchen and bathroom.