I think I know the series you're talking about, cuz I wrote it, so I've got a few ideas that might work. I don't know the first thing about coding, but if you need some writing done for like descriptions or events or whatever, I can do that if you want. You know what, I'll shill my hypno stellaris stories here, too, in case there's some hypno stellaris fan here who hasn't seen em.
www.furaffinity.net/view/35444809/www.furaffinity.net/view/36545351/www.furaffinity.net/view/39234128/So that being said, here's some ideas.
-Buildings, planetary decisions, or edicts that provide an enormous happiness buff
-Possible new buildings and jobs: for instance, a temple of obedience might produce one Master ruler job and four Pleasure Slave worker jobs. The Master job would produce maybe stability, influence, and a bunch of unity, while the Pleasure Slave jobs would just produce a lot of amenities. I like this idea because the building would produce everything that isn't "real": unity, influence, stability, amenities. Really gets the flavor of "this building is extremely culturally beneficial but doesn't actually do anything productive, it's just a bunch of sex"
-Possible events or anomalies that involve officers getting hypnotized, to various effect: maybe pirates brainwash one of your admirals and then you have to fight a big fleet, or maybe one of your governors accidentally gets hypnotized with standard breeder programming, so she now has huge tits and believes that only sex matters (so, maybe -15% resources from jobs, +15% pop happiness, +80% pop growth speed)
-Lots of stuff you could do with psychics, too (maybe this whole thing could be a civic where the species starts off psychic, and that allows opportunities for more unique story stuff or modifiers)
-One possibility is a unique type of building on resort worlds, maybe a hypno-embassy, that dramatically increases immigration pull and pop growth from immigration (you could even go above 100% if you really want everyone flocking to your planets)
-If you're going for a more military conquest xenophobe style, you could even add a new purge type (anti-autonomous hypno-integration or something) that produces, I dunno, consumer goods or unity or trade value or something, where the flavor is that the pops aren't being killed, but rather integrated into the hypno-society to the point where they are considered tools, not individuals, and so they don't occupy housing or have jobs.
Really if you're trying to make this lewd fun I think the biggest thing is story events that illustrate a fun hypno-universe. If you wanna add some crazy endgame stuff, make some really overpowered buildings that can only be created on planets with 100 stability.