I would like to build a duplex on it for long term rental income.

My wife and I are real estate investors based in Katy, and I/we are looking to connect with local investors, real estate agents, property managers, and contractors in the area.

I just started as a real estate agent and I am looking to build connections with investors.

You definitely can't just buy a building low down, do no work to it and keep old rents and expect to profit. 

@Anade DavisHi Anade, You’re on the right track with reaching out to your survey and engineering company—they often have strong connections to local contractors.

Hoping for $325,000 for the build (budgeting for $400,000 with overages).

I have a new build with Blacktip.

Quote from @Paul Gupta: Hi, in California, For jobs requiring a license, there was CSLB (contractor state licensing board) which would give either a General Contractor license, or specialty licenses by trade (~60 specialties such as concrete, welding tile, ) https://www.cslb.ca.gov/about_us/library/licensing_classific...My Q: does Maryland and DC area have similar requirements? 

I also really like the idea of building a brand that you could sell.

Call the contractors closest to your building and see if they can help or know someone.