I have "lunchbox lockers" (EZ, Lock Rite, Spartan etc) front and rear in a couple of Samurais. Both of these Samurais are setup for primarily offroad, and not daily drivers. On the road, the rear locker can be quirky, but still streetable. Some of the negative characteristics: the Samurai will pull to one side or the other when accelerating, there is a lot of driveline windup which can be a major pain in stop and go traffic, clicks and bangs on sharp turns into park lots etc. Again, they are pretty liveable on dry pavement.
I drive other Samurais/Kicks when it snows/ices so I cannot coment there. I imagine it would be quite scary.
If your Samurai is primarily offroad driven, I would go ahead an install some lunchbox lockers in your Toy axles. I wouldn't put a spool in the front though-you do want to be able to turn.