If it's more of a row house, you have a lot less yard to work with, so I would concentrate on simply making sure the yard is need and clean, then focus your energies on the front porch and front of the house.A few must do's for selling or trying to get the highest rent...Power wash the porch, front of the house (unless you have repainted) and sidewalk.  

I have 3 fourplexes with basically 900 sqft apartments.My "rehabs" so far are basically re-paint (walls, not trim), do minor repairs, replace carpet w/ LVT (about 650 sqft), replace carepet on stairs, and replace the countertops w/ pre-fab laminate tops from big box hardware stores.Materials and labor come in around $4500/unit when I do that. 

The room that was re-painted and cleaned for my occupancy was taken by a current tenant, I was to take her former room that was not freshly painted and cleaned.5.

@Agustin Conti In the case of these repairs to the driveway and patio/deck I would think they are solely cosmetic and at your discretion as to if you will pay for them unless your insurance company has flagged it and told you to repaint it or repair it which you did not mention so I will assume is a no.

To get a higher appraisal amount, I would like to repaint the house in order to make the house cleaner.Is there a solution that would fix the smoke/nicotine stained walls and keep it from being stained again?

The thing is, properties have issues that pop up after inspections, kids break in and repaint a room for example (LOL) so, yes, justify your offer.

I plan to repaint all of my rooms to a neutral color.My concern is, would I regain the money put into installing the floors plus some?

Requires some rehab, paint, bathroom I can place new tiles, new vanity, repaint the kitchen or maybe get a new one, nothing expensive, around 1500 plus install.

Otherwise, you can clean, repaint, repair missing hardware, and add storm windows and make them just as efficient as replacement windows - but a bigger hassle for sure in the future. 

I don't personally have any experience with buying a multi via FHA, but I can tell you from a seller's point of view ... having not dealt with the FHA inspection aspect before, I was amazed when my realtor advised that I'd need to, for example, repaint the eves of my house because some of the paint was flaking off, and that FHA would likely flag it and not issue a mortgage, because of something as minor as flaking paint ... the eves were freshly paint 5 years ago, mind you, so its not like they had been neglected for 20 years.