As far as just regular cardio, i.e. waddling away on a treadmill or something, you can do that pretty much everyday as long as you don't overdo it. Something like 20-30mins at 50-60% Max HR wouldnt hurt your lifts. And LOW intensity cardio like that actually helps you recover faster. Something about the way increased aerobic response shifts you from sympathetic to parasympathetic dominant.
For sprints, push's, hill sprints, whatever else you want to do, it depends on your goals as to where to impliment them. If it is just for conditioning purposes, do them after your workouts as often as you like. If you are trying to improve your speed and explosiveness, do them before your workouts, after a warm-up.
I only suggest this because I am assuming you are limited on time. If you can split it up throughout the day, do it. It just can't be optimal to work on so many skills in one session.
As far as high intensity on off days, thats a good idea. Like I said, the low intensity stuff won't mess with your lifts.