I'm wondering if there's a software out there that could connect 2 separate VRBO accounts to resolve this issue.

.: What is the average conversion rate for cold calling using software like PropStream, specifically targeting probate, foreclosure, or tax delinquency leads?

Quote from @Ryan Konen: You are correct that comping software like Privy, Propwire, and Propstream primarily rely on public records for their data, such as county assessor records, MLS feeds, and sometimes 3rd party aggregators.

Most of our clients are professionals - physicians, attorneys, software engineers.

Nathan above gave some good software recommendations, any of which would probably work well.

Based upon the screenshots of the software it looks like Investor's Edge software is just a white label of Propstream. 

Can anyone recommend software which would accept monthly payments (from me to seller) and create proper 1099 forms for tax purposes at year end? 

If I were you and you need to meet the requirement of working under a Broker, just make sure your agreement with the broker allows you to take all your properties with you once you leave, obtain your brokers license and start your own brokerageI would also start looking at software systems and joining the National Association of Residential Property Managers.

No data company is 100%.

Title company that does assignments ?