Some things didn't change, such as the requirement that the property be on unplatted land, so that definitely restricts the number of eligible properties. 

Requirements for Registered Agents: Recognise each state's criteria for registered agents.

Be careful contacting delinquent borrowers in states where your actions could be construed as foreclosure consulting, which may require a license and may subject you to civil/criminal penalties if you run afoul of the law.

The most important thing to do is either you or your wife need to qualify as a real estate professional (IRS definition, no realtor license required).

I have a listing for one that I think could be converted into a duplex plus a small mobile home park, but I don't know the clearance for services and the dwellings required in Texas. 

One advantage you'll have over people doing a regular FHA purchase loan (non 203k FHA rehab loan) is that when you go towards purchasing a 3-4 unit property and have to deal with " FHA Self Sufficiency," Rule you'll be able to use future market rents that are appraised on with after repair rents (way higher than your acquisition rents probably).This makes it easier to make your FHA loan qualify especially if you buy a good deal that has big rental income upside (your proforma future rents are way higher than your acquisition entry rents).FHA SS rule is required to qualify a FHA loan when its a 3-4 unit property, this doesnt apply to 1-2 unit FHA loans.Even on 203k FHA loans you'll need to meet FHA SS rules (3-4 unit applies to).

To start the process they require: 1) letter of intent; 2) lien release proposal written with attorney or title agent; 3) survey with descriptions of before and after.

🤔🤔Correct, experience is not a requirement.

Due to item 1, adding an ADU can require years to start achieving any return (once the accumulated cash flow recovers the initial negative position).4) Adding an ADU is a slow process.

Even then, they should be facing out to detect intruders, not used to spy on tenants.WiFi locks require a WiFi system.