I ask because as mentioned above if you have an investment that is  going to return 10%+ then does it matter what the rate is in the long run? 

A lot of times the different viewpoints lead to different questions to ask.In regards to your replies:1) I'm no legal expert, but it seems the sections of tax code you mentioned don't consider in-laws to be a personal relationship that would prohibit the transaction.

I would not advise buying the condos you mentioned above unless there is something that I am missing.

Not to mention staff, I’d check on the number required to stay up to ratio throughout the day, night ratio is likely lower than day ratio.

As mentioned above contact a tax planning specialist.  

Just curious, when you mentioned other strategies, did you mean strategies such as Air B&B, guest homes, glamping, things of that nature?

(May also cut significantly into the current cash flow on it)I know you mentioned not doing a HELOC on my primary, but wouldn't it be advantageous to have the ability to pay off the line of credit instead of be stuck in a payment that is much higher? 

It has been mentioned above but your best bet is to separate the SFR and the 8 unit into two separate transactions.

All groups have mentioned, wanting to try our hand at flipping independently, and I thought why not do it together. 

The markets you mentioned in your initial post in this thread are great markets, but they're all heavy on appreciation and light on cash flow.