Well congratulations, of all the people I read on this board if I had to elect somebody to parent, I would have voted for you first. Big changes indeed - biggest one I ever had in my life.
But, a word of caution - or at least a plea for really effective time-management skills - both of those things, being a parent, or running your own business easily are 30 hours a day, 8 days a week deals. And its not impossible, but it is weirdly difficult. Two activities less complementary to each other would be hard to find.
But hey, when my ex and I ran the club the kids were at the club, I had them taking tickets before they were 10. The younger one mixed his first band when he was all of 13, and most of it I never taught him, he just watched and learned. Though I'm sure that lots of people would not think a rock nightclub is the best place for kids to be hanging out, I always found that it - like everything else in show biz - is really the last family job where kids are always about (underfoot) and nepotism is not a dirty word, its a positive value. And they learned to work, for sure on that. When I was doing grad school and teaching I brought them with me all the time, their research skills - along with their ability to Xerox like a mofo - served them well when they went to college.
So I guess to the degree that you can incorporate them into each other, it will be a little bit easier. It's a balancing act worthy of Cirque du Soleil to be sure. But kids are flexible, and they pretty much grow up thinking (until they get to jr high/high school) that they way their family lives is pretty normal. I remember when the older one came home from school one day and said:
"Hey dad, remember that Arlo guy I went to breakfast with a few years ago?
"Sure, why?"
"Well, is he the Arlo Guthrie whose dad was Woody Guthrie and wrote This Land is Your Land? The same Arlo Guthrie who performed at Woodstock?"
"Yeah, that's Arlo alright."
"But he's really famous, how did I wind up going to breakfast with him?"
"As I recall he was really hungry, Mom was busy and I had class, so we sent you with him because you knew the way."
"But he's really famous."
"Yeah, but don't hold it against him, he's still the same guy you went to breakfast with, don't trip on it too much."
It was interesting when it began to dawn on them that their life was a little bit different, but not too much.