Not an official event coordinator, but I feel confident that if I answer they'll correct me if I'm wrong.
1. I'm gonna go with yes, but you should PM Bo. He's not an unreasonable man, there's been a "5 and under free" clause at 'Geddon before. But if you're trying to get in your 15 year old brother for free, well then yah he's gonna pay. When you pay for an event you aren't paying to fight. You're mostly paying to camp and for food, the fightings thrown in for free!
The event gets charged for having your youngsters body on site, so they charge you.
Half of Stone House Park's camping area (around half) have electric hookups. Events aren't like normal camping, you don't sign up for spot 135 that has electric and water. You show up, the whole camp ground (usually they'll have a map or something with areas) is available. Different groups have different spots they've claimed by camping in the same place for 2 full years now, in particular some groups even come on weekends and volunteer and in doing so spruce up their spot. In general lately most of the main middle island with the hangin tree is open lately, and I believe there's electric around there. Everywhere there is electric there is water, and camps certainly don't mind you using the water hook up, we like it when you survive. Just be curtious, and it doesn't hurt to ask an already pretty full camp nearby "Hey, does anyone usually camp here?" and if they say "I have no idea." move on and ask the next big camp.
I don't THINK chicken allergy should be a problem, it's gyros one night and brisket the other, but I'll let the official guys check that out.
EDIT: I just noticed you're info on the left their, so strip the "helpin the noob" tone out of my voice like I think you've never been to an event before. EBF I'm sure will be camping someplace with power. You're not trying to hook up an RV are you? That could be a problem.