I originally purchased this 2 bed / 2 bath single family home as owner occupied since I qualified for the down payment assistance program for first time homeowners.

Sorry your bed broke with the first guest.

So a three bed, even if the third is awkward, holds more value than higher end areas, where design and flow become more valuable.That being said, even if you convert this, legally, it will likely not be a true comparable to a traditional three bed house of similar finish and size. 

Look at similar 2-bed listings nearby to price competitively.

Quote from @Charlie Green: Just locked up a 3 bed/1 bath in Garfield Heights for $74k.

3 beds and 2 full baths.

But- Price, SQ/FT, Bed/Bath, Location is all comparable.What does your agent think?

Small 4 bed 2 bath walking distance to Valley View rented for $1700 monthly.$210,000VAContact me ASAP!!

and no one else, I would have been very skeptical why they need to lease a 5 bed/4bath home.

They definitely wont hold back. also might want to consider adding "Where you will sleep" in the Airbnb listing, so people will know there is a sofa bed.