In reply to BuzzI:
Assuming this isn't a troll:
I think you're biting off a bit more than you can chew at the moment.
I started taking my kids into the hills when the oldest was 7. But 1 on 1 for summits, until they were a bit older, as handling 3 kids simultaneously in a craggy environment was not something I wanted to do until they'd developed a bit of hill sense for themselves.
Also, as others have said, beware of "pushing them to achieve" and "challenging themselves". I used to cajole the middle one a bit as she tended to not have quite the "summit fever" of the other 2, but we'd turn back wherever we'd got to when it became obvious that she really wouldn't enjoy going all the way (and back). We'd find a turnaround spot with a good view or interesting stream or whatever, and have a break before going back.
I wouldn't have taken them at all if I didn't feel competent to navigate, and already had plenty experience in the hills myself. You really need to keep an eye on things like clothing with kids of that age....getting my oldest to pop a fleece on when we stopped was quite hard because "I'm very warm dad!"...but if he didn't, 10 minutes later he'd be shivering. Kids go from full-on to dead stop very quickly, and you need to be continually alert for signs and symptoms, especially with 3 in tow.
Wild camping on a summit isn't a good idea. They're generally rocky, exposed and not very flat, as well as not having access to water. There are plenty good wild camping sites a way below summits, but again I'd think hard about what gear you need, and who's going to carry it. Kids that age shouldn't really be carrying more than 15-20% of their body weight so for a wild camp YOU would be carrying nearly everything. When my oldest was 10 we did a 4 day wild trek in the Brecon Beacons and I think I ended up with about 23 kg on my back, carrying most of his kit and the food as well as my own. With 3 you'd REALLY be pushing it I reckon.
When we started doing Lakes stuff as a family, the following scenario worked well and was huge fun for the younger ones:
I drove up to Wasdale with the oldest and set up camp. We did a couple of days walking 1-on-1, including several summits. Day 3 my wife brought the younger ones up by train to Ravenglass and then got the "L'il Ratty" steam train up to Dalegarth. Oldest and I walked out from Wasdale over Burnmoor to meet them at Boot, had late lunch there and walked as a family back to camp at Wasdale. The oldest got a good 2-way workout, with a rest, while the younger 2 enjoyed the 1/2 length adventure walking 1 way across Burnmoor, still buzzing from the steam train ride. I think I only had to carry the youngest twice for short sections.
Given your lack of experience, I'd start out with something relatively benign, not involving a wild camp until you've built up some experience. A summit and down in one day is feasible with reasonably fit kids of that age, but with 3 in tow you'd need to pick it carefully with safety in mind.