Lot of stuff here and Bobby may want have some philosophy specifically for INFC. I can try to take these 1 at a time and give the rule and some interpretation.
Extra points: Rule - the holder may raise from his knee to retrieve an errant snap. Once he does he may run, pass, or return to the ground and place the ball for the kick. IF he comes off th knee and returns to his knee to hold the ball, at that point he is stuck. He may not raise again and run or pass. So answers to the questions...
1. Can the holder get up and run the ball into the endzone for the extra point?
--Generally YES. However INFC has a rule that if your kicker is a striper, this play should be blown dead. The reasoning is that they are making an exception to the striper rule by allowing him in the backfield. If he kicks fine, if anything else happens, play is over.
2. Can the holder get control of the bobbled snap from a kneeling position and stand up, run, or toss the ball to the kicker who runs the ball into the end zone?
--Again, YES. But again, if the kicker is a striper, this play is dead.
Also, with the onside kicks:
1. Can you make contact inside the 10 yard gap between the kicking team and receiving team during the onside kick if opposing players are inside this 10 yard gap?
--I posted specific rule reference and wording on another thread about this. The short answer is that the Kicking team may not initiate contact in this area until the ball has gone 10 yards, R touches the ball, or R initiates a block first.
2. Is it ok to make contact with kids away from the ball during the onside kick? Was told both ways during the season.
--It's never ok to contact a player obviously out of the play. So if the player away from the ball is trying to participate in the play, it maybe ok. If he's standing around watching the action across the field- it's a foul.
3. Are "gunners" allowed to make contact with the opposing kids to "blow up the play" and force a fumble? Was told this weekend that you are not allowed to blow up kids.
--maybe my interpretation of the question is wrong, but what I think you're asking is on an onside kick, can your gunner make contact with a receiving team player in an attempt basically take him out of the play?!?! See the answer to #1. In most of these situations the ball has not gone 10 yards yet or been touched by R yet. In this case, it is a 10-yard illegal block and if severe enough could be deemed a personal foul.