I live in Tempe, Arizona, which is the city of one of the largest universities in the nation (ASU - Arizona State University), however, very near to me (15 minute drive) is Scottsdale, a very affluent, popular, and relatively affordable suburbia.My question is:For my first rental property, a single unit house, in general, would it be better to get a Tempe house for the college student rental demographic, or a Scottsdale house for the small family of 3-4?

This popular meetup sounds great.

Do you understand marijuana is legal in Oregon and many other states after a popular vote of the people?

First step is to educate yourself on your market and exactly how you intend to perform the wholesale transaction as there are many ways to do it, not just by assigning a contract, contrary to inaccurate popular belief.You need to know your market, know how to estimate ARV’s and know how to estimate repairs.

I've also notice rooming houses becoming more popular.

It is not a very popular grant, mostly because of the math you have already figured out. 

Maybe that's not popular opinion of how to go about it, and maybe you won't get as many deals that way, but it will protect your downside a lot more than expecting the best every time. 

Series LLC are only considered an instrument in 18 states & territories but depending on where you live & where the properties are located, you can incorporate in another state which is why Texas, Nevada & Wyoming are popular states for LLC creation for real estate investors. 

This property's neighborhood is likely to be a very popular neighborhood with Airbnb customers, and short-term rentals can sometimes be a way to turn an unprofitable deal into a lucrative one.

In my honest opinion, I believe multifamily will be appreciating better due to the popularity of house hacking.