When I was 16 I wanted to be in a band but couldnt afford instruments or lessons.

This has been instrumental in being able to do BRRRR deals.Also, you will find your team members over time. 

A HELOC is a great short-term instrument.  

So, what instrument/document is causing this issue? 

Any instrument can be used.

It is certainly possible to find a lender to give a credit line, however, I would say that in most cases, it would not and should not go unsecured, thus, a deed of trust or similar security instrument should be required and used.

In most states a DEED, is a TRANSFER INSTRUMENT, not "proof of ownership" like on a car.

decide if you really really want to be a landlord for the rest of your life.or if you would like to look at other financial instruments that will return as much with much less work.or buy a business that makes any of the standard investments pale .. if your going to put time and energy into something maybe owning a cool little business that makes you 100k or more a year would be fun and profitable.

Next, the putting together investors for funding" aspect is highly regulated by the SEC, that can easily be viewed as a security instrument and a violation of law.

Your findings that you discover from your research will be instrumental in you starting out in investing.