Do I need to stretch before even short exercise sessions like the 7-minute workout?

Yes, here's why. When you exercise without stretching first, you run the risk of injury, because your muscles are still tight. That is the reason, it's important to stretch out before exercise.
Sincerely,
Selmaan A Ali

I always stretch after my workouts and in the morning after getting out of bed.

I don’t always stretch before a work out. If I feel super tight in the muscle group I will be using I may do a couple of minimal stretches. The key is my warm up to get the muscles to engage.

My yoga is not my stretching!

Stretching should be done before any kind of activity, even the minimal ones. Stretching is also good to do regardless of any pending physical activities, even if you will not be doing a physical workout your body still needs to loosen up from being still/tightened over night or even periodically throughout the day. Stretching can help relieve stress as well as promote flexibility and energy. Stretching is something that should definitely be done every single day

Yes, stretching before doing any exercises – short or long can help your body prepare for the session and assist your body to move without injury.

You should just start slowly. Stretching first isn’t even the best idea since you don’t really want to stretch when your muscles are cool from not moving.

It can sometimes be a good idea to stretch before even a short workout. You want to make sure that you don’t pull any muscles when you’re doing any sort of workout, but you must also be careful when doing stretches first thing in the morning. If your muscles are cold, stretching could do more harm than good if you don’t warm up your body beforehand. One thing I often do in the morning is do my workouts after waking up, and I’ll often do some jogging for a few minutes before doing some serious stretching for the REAL workout. I learned this from my martial arts instructor and the tips I’ve gained are very crucial.

The best way to combine streach and workout is as following; start with an dynamic streach, then do your workout and finish with an long hold streach.