If the explanation is the somewhat prosaic "they just happened to be there" I'd hazard to say that Aslan immigrated to Regina out of choice. As "cultural Aslan" who were happy being "cultural Aslan" would have never immigrated to Regina. They're likely to be middle or upper class Aslan (the poor are unlikely to have been able to trek that far) who were dissatisfied with living in culturally Aslan worlds. Some would be outcasts but many would have come to Regina out of some weird choice. Regardless of the cause, such Aslan would be predisposed to be willing to discard or at least suppress some of their culture/biology to "fit in" with the majority society.
A player in my campaign played an Aslan male. I do allow (in some circumstances) a PC to do chargen in more than one career, and this one was "special".
We were doing AM1 chargen, and he failed at Wanderer (failed survival roll in his last year of the first term). I use the "courtsmartial" option from JTAS (with modifications), and he ended up being
forcibly drafted by the Navy instead of imprisoned.
He then failed another survival roll the last year of his first term there, and
deserted (stealing a small cargo ship with a 30dt fighter inside).
From there he ended up as a Pirate (giving up the cargo ship in order to "enlist", but keeping the fighter), but (you guessed it) failed survival in the 2nd year of his first term, with a result of
mutiny. We decided he was one of the mutineers, and it was successful
From there he decided "the Aslan Way" was not for him, and ran to the Terran Confederation (this is in the prolonged Terran-Vilani Conflict period, which replaces the 2nd Imperium period in my TU).
Since he had yet to complete a single full term, I allowed him to enlist in the TCN (using Book 5)... where he spent 3 full terms as a fighter pilot (mostly with "special duty" units, thanks to his personal Aslan 30dt fighter), retiring highly-decorated with the rank of 05!
It seems he was much more at home aboard Human military spaceships than with other Aslan!
It's likely that the Aslan have special laws pertaining to them (as probably do almost all non-human sophonts); I doubt that Aslan dewclaws would have be surgically removed or blunted, however an assault using them would be considered assault with a weapon. I'd say that Aslan, especially male Aslan probably have some method to "blow off steam" perhaps in the form of some sort of "arena athletics" (basically combat) where they can go to get into tumbles with other Aslan. This would allow Aslan males to blow off the frustrations of suppressing their instincts (if indeed a lot of those things are actually instinct instead of culture). They'd be community gathering places; non-participant Aslan might watch over a few beers (or whatever Aslan drink). Conversely, such combat might be popular with non-Aslan as well with teams, fans, and viewers across Regina and the "stars" having household name recognition amongst humans.
In a more radical twist, integrated Aslan might be strongly matriarchal. Since female Aslan are more likely to have skills and mindsets compatible with humans, female Aslan might make a lots of money and in human society money = power so they might have the power in Regina Aslan households. A human that holds talks with an Aslan executive might automatically assume the executive a female, so would go down to the local grooming combat place where the executive and the Aslan (presumably female) could discuss business over a meal while they watch the Aslan's husband fight in the arena, allowing the female Aslan to show off her husband's virility and fighting prowess and by extension, her own power at being able to woo such a successful mate.
First rule of Furball Fight Club is... NO CATNIP!!
Aslan Mixed Martial Arts Leagues!
