I'd do that but I don't think the Rangers would.

Decent return for hanifin

I think the flames would rather get laffy tbh, I’m sure the rangers would still accept if it was laffy over kakko

When I put this together I factored in that both teams are tight on the cap and need to trade dollar for dollar. Kakko is trending the right direction and he fits with the Conroy philosophy, get younger and bigger. He's also considered a underachiever at this point, so he does have a probability of being traded. Scheider is from the prairies and would be GREAT depth and is still developing. Schneider also evens out the defence for defence part of the trade. Vesey is simply depth for the Flames and helps even out the cap issues both teams are dealing with. Hanifin answers a big hole the Rangers have right now as they are in a win now situation and gain 6 yrs experience on Schneider, with plenty runway left in his career. He can easily play with either Fox or Trouba, giving them a solid top 4 defence. Hanifin would also have absolutely no issues going to NY, close to home and going to a winning team. To bolster the trade the Flames could up the draft pick to a 3rd or even a 2nd, as long as the Rangers upped the 5th to a 4th round pick. The Rangers would be adding to the defence now, but thinning out their forwards a little. The other trade I posted was Vladar going to Arizona for Valimaki. That opens up the cap space and adds another quality young defence depth. That trade lets the Flames carry a 23 man roster, where they have to carry only 20 currently. Arizona would be basically getting Vladar for free, since they got Valimaki off of waivers.

The Rangers aren't trading Laf under any circumstances, but even so the real issue with this trade (as made by the OP) is Schneider, not Kakko. He's being explicitly molded into Trouba 2.0 and will slot into his place when Trouba retires or leaves. He's a part of the Rangers' long term plans just like Laf, Chytil, Fox and isn't going anywhere.

As for Jimmy Vesey I don't see the Rangers shipping him off either. He's defensively great and very cheap and there's really just no need to get rid of him unless they have a replacement lined up that is as good as him (and as valuable contract-wise)