I had played once in a lifetime, so yes, I believe you are right in thinking Chop Chop is going to be more than he seems
Nope. Once in a Lifetime shares the same setting as Eternum, with the latter taking place more than a decade after the events of OIAL. The info about it is posted on the FAQ page on Cari's Discord, with the timeline based on what Judie said about Eternum launching a year from then and Orion's monologue where he said that it's been more than a decade since release.
Also, Orion's monologue at the beginning mentioned "Former President Stabb (Michael Stabb was Stabby Mike's real name as revealed in the OIAL Harem end)," so yeah it's been a while ever since.