Dear A.,
It's been my experience that early risers are just simply that...early risers. My daughter was always up very early. And my nephew...when he comes to stay with me, he's up before dawn. Even still, at 17 years old!
My son, on the other hand...unless he knows we're going on a trip or he's up early to go fishing, I practically have to drag him out of bed. I've literally threatened to make him go to school in his underwear if he doesn't get up to get dressed.
Early risers are actually easier, and although you can't change when they will wake up, you can let them know that they can still be quiet. I told my daughter and nephew...."You may be awake, but the HOUSE isn't awake yet." They could color or read, quietly listen to some music, play Barbie's or Lego's, get dressed if they wanted, but no getting into the kitchen, no turning on all the lights and TV. Obviously, as they got older, they could help themselves to some toast and cereal or something. But, they had to be quiet if everyone else was still sleeping.
I have two kids and Lord knows I've been up all night with one sick and didn't need the other one banging on my shoulder at 5:00 to get up when I'd just laid down and finally konked out an hour earlier. "Go back to bed!"
If you've got little ones getting up at 6:30 or 7, count your blessings because that's way easier than 5 or 5:30, trust me.
School will be starting soon. Lay out their clothes the night before. Make sure they have a lamp they can turn on and puzzles they can do. Give them a tablet and some crayons. What time does your alarm go off? 7am doesn't sound unreasonable, but perhaps you're a night nurse or something. I was going to say that maybe you could get your older son a digital clock and tell him at such and such time is when everybody gets up. He may be awake earlier, but that's not the get up time for everybody.
I've always said there are two things you can't force a child to do:
1) sleep
2) eat
Chances are, you kids will always be early risers so you just have to try to work around it.
I wish you the best.