I was told that you just form a standard LLC and I would just list my current LLC as a managing member.

Conventional financing is geared and regulated for the owner occupied homeowner and is designed to protect that borrower from poor lending practices.  

Here are some practical steps you can take:First, make sure you have a clear and comprehensive written agreement.

Think of a tool like FollowUpBoss, but for PMC's and MF professionals, instead of realtors.We wanted to create something that can aid a standard PM software, and help PMC's expand thier portfolio without having to onboard a bunch of agents, automating the entire leasing process.Do you think a tool like this is needed?

I'm open to new ideas to learn.I'm curious to know: what is a standard or average seller finance deal? 

At a bare minimum, I would require a written lease agreement and a standard security deposit equal to an entire month of rent.

That's a standard cookie cutter deal that I have gotten 90% financing on for 1st timers.You have to get in a market where 50k let's you play. 

It's the same principle you would practice with a mutual fund: it continues to grow (hopefully) and you pay a tithe from the prophets received at the time the profits are received.I am not strict about this by any means, for myself or others.. what other people give is not my business and I do not believe in people giving under compulsion.

Standard heloc cost on a 100k @ 5%, 10 year term(int and principle)= 67k in interest.  

Unless you find an attorney that exclusively practices in this area, they won't have that level of knowledge.