When partnering with someone make sure you build a relationship first because end of the day it is not just about the property, it is about the partnership. 

I am a bit anxious about the kind of relationship I should foster with this tenant, and balancing the relationship between roommate and tenant?

Local relationships are good, but conventional lenders have the same line of products...the creative lenders will have a very different portfolio of products...the product you need may not be offered by local lenders in your area.Lenders have zero influence on the deal itself outside of what an independent appraiser/inspector relays to them...local knowledge of markets is not in play at all.

Was able to beat out other offers but creating a genuine relationship with the listing broker.

Was able to beat out other offers but creating a genuine relationship with the listing broker.

With SFR I would rent by the rooms (non-family and non-friends, or family and friends who will not take disadvantage of relationship).

I would reject because one has no income, but you can't do that in California if the other has enough to cover the rent.Students don't have jobs, but they have income from somewhere, otherwise, they couldn't be going to school.See about a parent co-signer for the student.First time living together in a romantic relationship is pretty iffy.

As a newbie to the real estate world, I’m eager to start developing my network and relationships.

If you're looking for a bank to handle your team's LLC, then any is fine, although you may want to establish a banking relationship with a lending institution that services the type of deal you may want to handle on your own with your holding/operational LLC  - i.e. buy and hold SFR/MF, fix and flip, or ground up construction.

The key is developing good relationships with each.