When I asked the seller for receipts detailing the work done and requested permission to speak with the mitigation company directly, he refused.

You can ask the Qualified Intermediary directly when they refer you to someone whether they are getting paid for the referral or merely referring you in order to help you.  

Also the Voucher doesn't cover the security deposit which in most cases, I have to put my S8 tenants on a security deposit payment plan for those to get them qualified to move-in on my applications.

I have had luck with doing direct mail marketing for some of my past clients that wanted a certain area or neighborhood, you'd be surprised at how many sellers don't want to deal with showings and everything else that goes into listing a home. 

I'd do it now because you want to make sure the rent for Jan is paid directly to you. 

You want to be working directly with the handyman, not the "GC" who is delegating and not doing any of the work.

@Chirdeep BhutaniIt's market specific, but residential RE and commercial are not always directly correlated. 

Would it be better to start with SFHs or dive directly into multifamily?

When I pressed them about the dead LLC they said that the error must be on my end.Screen shot directly from the Ohio Secretary of State website below.

I’ve already found some potential buyers interested in the deals.However, one buyer has recommended that I terminate my contracts with the owner and instead work directly with them.