Insights in other's BRRR model with investors

[Gina Shumway]

I am wanting to BRRR. I have 2 investors. May I ask the following:
How do I refinance with a 30 year mortgage with investors? I don't know if they would want to be on every loan (nor do the work). 

Do I form an LLC with my investors, but then go get a conventional cash out re-fi myself?

And how do taxes work if I didn't form an LLC so we could get a conventional loan?

I hope this makes sense. I had planned on doing a joint venture or LLC but then was told i could not work with mortgage lenders and I would have to go through a bank. How do others do this?
Thank you for all your insight and help!