One unit can be enlarged from a studio to a 2-bedroom, and we're also planning on converting the garage and part of the basement into a fifth unit.Now, we're faced with a difficult decision.

Enlarge the opening.I bought a three bedroom house at Auction.com site.

They are appraising as 3 bedroom, not sure how that works. 4) The AC is 16 years old and will probably need to be replaced soon 5) The hot water heater is also old 6) Crawl looks clean but there are rodent boxes down there-like the ones you see near businesses so wondering about that 7) The house was in disarray, needs new carpeting and paint and some work in kitchen, no hardwoods.Would need upgrading if re-selling 8) master is odd, no linen closet in bathroom but there is one in master bedroom 9) no laundry room- they have the laundry in a bathroom in the kitchen. 10) The entry is odd and unusually narrow, as if they enlarged a room and it encroaches on the entry. 11) bathrooms are small.

Instead, I’d like to enlarge the existing unit and add a second unit, and keep the units as a rental over the long run.Which would be the best professional to tackle this layout?

Moved AC to attic to enlarge shower space.

Moved AC to attic to enlarge shower space.

But if you can take long view and can spend a little bit of time - it is achievable.Think about it, historical home appreciation rate in US is 3%(pretty similar to inflation rate), if you put 25% down, the implied appreciation rate enlarges to 12%, even if the cap rate and interest rate are the same, let's say 4%, the total return added up is closed to 16%.You do not need to spend lots of time to search for properties, you just need to buy in a growth market (with good population and income growth), good neighborhood and average properties, and hold them long, then put in a good property manager. 

can the Appraiser enlarge the area he is including? 

Click on the image to enlarge it.

How much will it cost to enlarge either of those.