Just because a KJ isn't a rockcrawler deosn't mean that a locker can be handy on muddy roads, soft muddy grass etc.etc.
I use Detroit lockers in the rear that way I can get use from my locker every single day, snow, dirt, mud, gravel, pavement, grass. I'm not paying $1000+ for a selectable locker I'll only get to use once or twice, I want something that'll be there when I need it in a split second all the time without hampering me on grippy trails.
But a Detroit or Yukon Locker isn't the choice for a short wheelbase KJ that sees much snow unless you have some less aggressive winter tires.
So overall, I'd also skip it and stick with what you have, and put a Warn M8000 up front.