He still thinks his dad and Saki would've benefited from actually discussing why she took a job at Junes, but they never did. His dad also has a bad habit of leaving dead family members on the store till.
He would be much more upset about accidentally doing the latter to Kanji than the former. PTSD is what it is, but he was as much into the crafty shit as Ma Tatsumi. CRAFTY SHIT IS NOT UNMANLY.
Neriel: Same first hat, less Complicated. She still trusts that God knows what She's doing and hasn't felt the need to make Her share with the rest of the class.
With Yusuke tbh I have to wonder if that's why he has a particular fondness for Sojiro. Not precisely a father figure but Hey! An adult man who isn't an asshole!
The closest thing she has to a dad figure is Aziraphale, which is one of the reasons she believes the well-adjusted cishet man to be a myth. Even if Aziraphale were a cis man, Hetero He Is Not.
Regulus... well, what we have about Orion Black in canon is a name, birth and death dates if you want to take Jo's word for it, and the fact that at minimum he enabled Walburga's abuse of her children by not throwing her the fuck out.
Also he's as gay as his elder son is, and figured if he lacked all interest he might as well spare everyone else the worst of the lot. Speaking of decisions he mostly regrets. The kids were a good outcome, at least.
And to explain why she'd never been mentioned before, they went 'uhhhhhhhhh she's still Artifact-whammied and we can't fix it, and while affected by this thing she accidentally killed your parents.'
The show also had a tendency to take what could've been a normal tragedy and backtrack to 'well ACTUALLY a supernatural tchotchke was involved!!!' which... I don't like so much.
Also he's as gay as his elder son is, and figured if he lacked all interest he might as well spare everyone else the worst of the lot. Speaking of decisions he mostly regrets. The kids were a good outcome, at least.