Once I dug into it, I may have even stopped working with the provider depending on what I found.

Depends on each owners personal situation.  

This depends on many factors, including the frequency of flipping transactions done by your Solo 401k.

Otherwise the cheap option is using a website online with the attorney going back and forth answering your basic questions.You might could see an attorney local  in person for 200 to 300 depending on rates for the area and bring all your documentation.

Let me know if you need advice on some of the meetups, I've been to most of them, some will be more helpful than others 1 depending on what you want to accomplish and 2 where you are starting from.

And depending on the amount I take out my cash flow from my first(current) rental may pay for those monthly payments on the heloc.  

Lending laws will vary depending on states, which I'm sure you know. 

It depends on your taste.

I was more so looking at a buy, rehab, and rent situation, with the possibility of flipping depending on the metrics on the buy.

Know lots in that area that are dependable.