The Greek name used in-game is (again) a bit misleading and inaccurate. Seleucid military colonies were actually called “Katoikiai” and the settlers “Katoikoi”.
Here are two good articles I found on the matter:
http://www.ime.gr/CHRONOS/06/en/society/index104.html
https://www.academia.edu/13665364/katoikoi - requires registering an account I think. So here is the pdf:
katoikoi.pdf
Pr for the colony and the wonder: https://github.com/TheShadowOfHassen/0-ad-history-encyclopedia-mod/pull/140
I'm not happy with the wonder article, I could find almost no information on it. However, that current article will work until I have the means of doing more research. (As in resources not time I need more history books.)
Similar to what the Ptolemies tried to do, the Selecids also invited Greek colonists to settle in their lands in the East. The colonists would then be beholden to the Seleucid for military service in exchange for gifts of land.