@Haylee Methvin Good evening, I can give my opinion on a few of these questions. I am a Realtor out of Tyler and know a bit more about rural areas around my area than Longview's.
-Fencing at least the backyards would be a bonus for tenants. It would give each tenant their own space. Also, it would cut back on other tenants "encroaching" over imaginary lines of the other tenants spaces.
-Garages would be a nice addition, but I would think you need to check the surrounding places and see if that would be a huge step up or not. Carports are not near as expensive, and less for tenants to tear up. If a lot of the other rental properties don't have any covered parking, then carports would be a much preferred option.
-As I am sure you know, building yourselves would save money, but maybe not time. Maybe that would be a better option after the first couple are built?
-House hacking would be a major benefit. You would have more options as far as construction loans for sure (If you are needing to get a loan). For instance, the construction loan I got to build my personal residence only required 10% down. If I were to build any type of investment property they would most likely require 20%. If your land is paid for, or maybe have some equity in it, then that could also help with down payment.
Hopefully some of this helps. Good luck on your journey!