I don't know what your market is like, but I feel like highest sale price would probably come from selling them individually as single family houses to retail buyers.  

I would encourage you to find a group of like-minded individuals and hang with them.

Does each unit have individual laundry units?

There's no rent control and the rental demand is very high. 

With the really strong demand the best properties are getting purchased very quickly and often for above the asking price.

They would be the best source to confirm vacancy rates and demand for specific areas.

Those two should give you a sense of demand and pricing.

you can convert that one too.Apartments rent on AirBNB all the time, no reason you can't do it - but of course, check out what comparable units in the area are getting, get a feel for demand and occupancy rates, make sure it's going to be worth your while before you proceed.

I also stack my showings 3-4 deep so the potential tenants can see how in demand it is and off set any potential no shows.

If you want to factor in utilities and furniture for the house, it's about 9-15 months before everything is paid for with the profits generated by each individual STR.