Also in the beginning, establishing communication frequency and other expectations.

Should I have this established before purchasing a property, or accumulate it over time after making a purchase?

Most well-established companies will operate in depts like you mentioned the new company does.

I am providing SEO and digital marketing consulting for a design-build firm operating in established and up-and-coming luxury mountain communities in the Colorado Rockies.

If your goal is to eventually solicit from people who are not your friends and are looking for passive income, then you need to consider establishing a syndicate.

Establish Track Record (Small Deals & Personal Equity): Most GP's start by acquiring/developing smaller properties where they alone can fund the equity side of the capital stack (IE - no raise). 

I could just get better at establishing relationships with the trades and hope that my cost to manage will go down in the future.

This is where expert due diligence comes in, so as to avoid gambling away your business.Expert due diligence is crucial when it comes to business transactions.

Also, is there any reason I would need to establish an LLC?

It sounds like you should bring on an established PMC as a partner to help walk you through the steps of growing instead of trying to learn everything on your own.