@Sung Yu You can 1031 exchange your fourplex into a single-family home, provided it’s initially used as an investment property (rented for 1–2 years) to meet IRS requirements.

Instead, the code is now written that I can build as many units as I choose as long as they meet building code and the total floor area to lot area ratio is 1 to 1 (the lot is just over 6000 sf). 

Look on Facebook as well for local investment pages, you will find a lot of local investors that you can meet with. 

Or you can directly meet them by registering to real estate events around you: https://www.biggerpockets.com/forums/521-events-and-happenings 6.

How do you build trust with homeowners or sellers when you can’t meet face-to-face?

@Jennie Berger The RS-3 Zone allows for Single-Family residences & 2-Flats as "Permitted Uses"; however, the RS-3 Zone still requires 2,500 sq.ft. of lot area per unit (i.e. 5,000 sq.ft. for a 2-flat) unless the lot meets the exception for the characteristic of the block as previously mentioned by Nicolas; then it can be reduced to 1,500 sq.ft. per unit in order to construct a 2-flat.

Meets at the Dave and Busters in Euless.

Find a good lender, get pre approved, make sure you practice running the #'s using the 100's of videos and guides from BP, find an investor friendly Realtor, and then start making offers on any property that meets your goal.

There are some great meet ups in your area I'm sure and a lot of people at those meet ups are more than happy to chat and give ideas and answer questions.

It'll be fun to grab coffee and meet up!