My parents pay for pretty much all the bills until I graduate college in 2 years.

To pay first property gains ($2k/month) to other property monthly EMI, both properties should be on same companies name or both should be on two different companies or both companies should have a common parent company?

A local bank allows the minor children to manage their own accounts on their signature with the parent's consent when opening the account, so they manage their savings themselves.  

(Apologies for my greenness showing, I've only ever gone from living with my parents to renting from landlords, I've never even thought about buying a home/multi-family to fix up then rent out myself til a couple months ago)

All of our friends that went away to college are now moving back in with their parents, and I am seeing this as a great opportunity for us to rent out one or both of our spare bedrooms to our friends.

Until we take responsibility for it and learn to control it, we forever remain a child. 

I have recently been promoted to property manager for my partner's parent's property that they just purchased down the street from me.

Indoor drone flying classesPet shop and play area for kids while parents shopSome apartments Actual car drift track?

My parents live in Redlands so I'm through there a lot.First, learn to work the numbers.

Luckily my parents(engineer/accountant) are very supportive and can be a second and third set of eyes (in addition to this forum) to make sure that, if anything, I don't start off investing in something that is a disaster.