I have used Washa Construction (http://www.washaconstruction.com/) more than once for residential.

Most likely your zoning will not allow a mobile house trailer mixed with stick frame construction. 

Keep in mind our current rental is 100% paid off.2) Can I get a mortgage for this building while it is under construction?

I once owned a small sub-contract construction co and have built home from the ground up.

.), laying carpet, ,texturing, painting walls, then get a second job as handyman or contractor and learn any construction skills.

So more then happy to connect and speak to every one that has questions, comments, and concerns.We are also building New construction rentals ( duplexs and quads where we can ) but hard to find land that is approved for the Quads.

Construction***Thanks for the reply.

Regardless of what I had I stayed in the construction business.  

And if you do not know a lot about reno's/construction I really would hold off, or do a JV with someone experienced. 

*Property Tax*Maintenance Risk*Actual Construction Cost - you said paint & carpet that can be very relative*Vacancy*Time back to market post tenant turn---------My answer is no this is not a turnkey rental, again, this based on the true definition of Turnkey - How do you intend on managing it for the individual you plan on selling the note to?