Trust me. Coffee is my best friend but I do know that my body has completely undergone hormonal swings. Even my partner says that my lack of sleep and increase in coffee and Red Bull has changed me.
I'd say try to adjust your schedule to allow (at least) 7 hour good quality sleep[1] and at least 45-75 minutes of exercise daily.
You'll have 15:30 hours free :-)
[1] Getting a good sleep involves a good bed, freshly oxygenated room, right temperature, no room, no iphones/ipads/e-devices, no video-games, no-movies etc.
7 hours of sleep with a full time job, a startup, kids and exercise? Is this even possible! One great life-hack we have is to sleep with the windows open and with thinner sheets. We both feel more refreshed the next day. And apart from the alarm clock, there are no devices :)
Whatever works for you!!! Meditation it is!!! (will try also!).
Have you looked into High Intensity Training? That allows you to pack solid, proven exercise techniques into very short spaces of time.