It's rather busy considering you're just starting back, even though it's cardio it's still 6 days of training. I'd
Suggest training weights Mon/Wed/Fri & keeping it all fairly simple.
Agree. I've been down the herniated disc road before and I learned that it often takes longer for weight lifters to heal their backs simply because their lifestyles revolve around putting repeated pressure on the spinal column. Starting very, very slowly and listening closely to pain messages is your smartest move. Actually, doing a 6-day split isn't a bad idea as long as you do a tiny amount on each day to start. I mean tiny.
The thing about herniations and such is that it's not just the injury, it's the body becoming inflamed around it. Inflammation sucks on its own and can lead to even more crap, notably immune system breakdowns and digestive problems. You can literally get sick from being injured; it's a stress thing. The body isn't designed to be stressed out for long periods of time, it wears down. Never a good idea to simply pop an Advil and call the inflammation solved, either. That's like putting black plastic tape over all the warning lights on your dashboard and declaring your car fit to drive. You ain't a Camry: if the transmission falls out of your body, your body never runs the same again, no matter how many mechanics you see.
I know it bites the big one to move forward so slowly (boy, do I know) but it beats getting re-injured over and over again and then waking up in middle age in more pain than a bull rider, unable to even sit comfortably. Hopefully, you already know all this, have assessed your abilities with a sage eye, and are taking each step like a seasoned pro. Oh, and one more thing--don't worry, you'll like this one--slow changes are easier to maintain over the long run. It's less like "training to cut" and more like "learning a new lifestyle of awesome." Then, you won't even have to think about lifting the way you need to, it'll just become a part of who you are.
See you in the gym.