I know mine went down one year when I got an exclusion for a metal roof but my payments never changed. 

I did check the Virginia Residential Landlord Tenant Act, which states that an application fee "shall not exceed $50, exclusive of any actual out-of-pocket expenses paid by the landlord to a third party performing background, credit, or other pre-occupancy checks"

I would recommend looking into the specialists in your area that deal exclusively in multi-family investing.

First it would be good to define your path in REI and your goals.Do you want to wholesale exclusively?

If you do this then you would be eligible to both take the primary residence exclusion tax free. 

I've joined a company and have access to their exclusive and non-exclusive listings-- but I'm unclear still if those are the ONLY properties I can show potential clients? 

As several others stated, you would lose the section 121 exclusion capabilities forcing you to either 1031x in the event of future sale or pay capital gains taxes if a gain is realized.

Trust account for security deposit - as name says it all, this account is exclusively for tenant security deposit only and independent from other accounts.

@China SistrunkI use RPR which is exclusive to Realtors.

I intend to live in the upper unit for at least 2 years minimum so that I can qualify for the section 121 capital gain exclusion.