IR-2 visa in Haugue Countries?

[Visa?? 1]

Hi, my husband and I are both US citizens but have been living in Haiti for 5 years as missionaries. We are caring for two children who we will be adopting, but are just trying to find the best route possible for our case. Instead if doing the typical international adopting and immigrating our children on an IR-3/IR-4 or IH-3/IH-4 visa, we would prefer to do a domestic adoption here in Haiti (which we meet the requirements for) and then immigrate them on an IR-2 visa.

We have recently contacted a US immigration attorney to guide our case. The problem is that Haiti recently ratified the Haugue. Our attorney isn't sure if it's possible to obtain IR-2 visas once a country becomes Haugue. Does anyone know if this is possible? We are aware that we have to have an adoption decree as well as 2 years of legal and physical custody of the children. We are just wondering whether this is even an option still.

Also what does it mean to "Habitually" reside in the US? We. Both lived there for over 20 years before moving to Haiti (we were born there). We are legal Haitian residents, pay taxes in both countries, but our lives are fully here in Haiti, and only visit the US once a year for a few days.

Thanks