As people mentioned, not only are those not Nill moves, but you might have forgotten some pretty important things about Mike Ribeiro's time here:
Disturbing allegations emerge in Mike Ribeiro sexual assault lawsuit
That's on top of the drug problems he dealt with while he was here, and I think some other run ins he had with the law. Again, 'character' in the NHL is pretty fluid.
Secondly, you really want to try and build a dead puck era Devils team? Teams don't play like that anymore, it's outdated. It no longer works. St. Louis had plenty of skill for their cup run. Ryan O'Reilly, who ironically, is the player we keep trying to draft over and over in the first round, has come with his own issues. Mostly that his dad is a pain in the ass and has meddled in contract negotiations in his time in the NHL. It's why he got shipped to Buffalo in the first place. I'd also argue that team is a massive cup anomaly. All credit to St. Louis for winning the cup, but it might be one of the weaker rosters to win a cup, along with the Hurricanes that won during the beginning of the post lockout era. Here's the roster, you can judge for yourself.
St. Louis Blues 2018-19 roster and scoring statistics at hockeydb.com
I don't even know what 'antics' you are talking about with Raty, Raty has not had character issues at all, he's had issues with not improving very much, or even regressing, as compared to an excellent season he had two years ago when he was considered the #1 draft pick for this draft.
On another note, I don't think the Radulov signing was that risky, at least no more than signing a guy that age can be as a UFA. All the stuff we heard about him was from his much earlier days in Nashville. There's a solid 4 years between his random end of season stint in Nashville and his time in Montreal, which is far removed from his more notorious time as a rookie. He got scratched for missing curfew with the Predators during their playoff run in 2011-12, but I think he was just playing out that year so he could get out from under the Predators owning his rights. Khudobin got in trouble for the same thing this last season I think.