Jack and Jill first time buyers that only use traditional methods of buying off the MLS may be buying at the top of their market cycle, but maybe not. 

Do you think it is better with the traditional way of just going with friends and family and building out your investor group? 

I will link a couple articles and will still swing back for more questions, but I mainly wanted to help the OP recognize that through the use of a Land Trust the Due on Sales Clause can be avoided.https://www.biggerpockets.com/renewsblog/the-traditional-llc-vs-the-series-llc-which-is-better-for-real-estate-investors/https://www.biggerpockets.com/renewsblog/2016/07/17/real-estate-asset-protection/

If you are buying and holding my suggestion is to do a traditional refinance so you can have a fixed payment. 

Many of which is already found in traditional rental agreements.

Buy and hold MFH is my strategy.After a few months I found a property which would meet my requirement of 15% CCR with traditional financing.

Paying a buyer's agent 3% is far more palatable to me than the traditional alternative.

Traditionally a mentor is not a paid position and good investors  dont sell good leads. 

Traditional banks with Fannie / Freddie / conventional loan types will sometimes push back on the LLC issue, but there is a BIG world of funding and lending for investors outside of that box.  

I don't flip, but from my understanding you would not use a traditional bank to get these loans unless your rehab is over 6 months, you would use a Hard Money Lender.For long term buy and hold I would leverage the duplex and buy more properties, and then I would use the profit from wholesaling and flipping to buy more properties.