If you have not yet spoken to a real estate attorney and tax/financial advisor you should do so. The "rules" and affects are differnent for non owner occupied properties vs owner occupied, plus your tenants have rights too. Visit
www.hud.gov for starters, but each city or county can have additional protections for tenants (which is another reason to talk to the attorney).
As far as your short sale to attract a buyer you need to be priced at current market value and then buyers will come, but the hurdle is getting your lender to agree.
Good luck