ugggghhhh I hate these huge posts answering the whole endurance vs strength stuff.
There all important. You also left out strength endurance. Theres no reason you can't strength train and then grapple hard in BJJ and acquire all the endurance you'll need (for the hobbyist).
If you don't have much time for outside workouts (say only 2x a week) I would suggest something along the lines of Ross Training or CrossFit (like the Fran and Grace workouts).