As an LDS Webelos Leader myself, I confess I have indeed seen a few leaders who seem to shrug Boy Scout training off on to the shoulders of the 11 year-old leaders, but I don't subscribe to that kind of lazy mentality. I firmly believe that it is my duty as a Webelos Leader to ensure that every last one of my boys enters the Boy Scout Troop fully prepared with the knowledge and skills they need to start off successfully.
As I have mentioned in other threads, my success is measured by each boy's ability to earn the Scout rank within 1 - 3 weeks of crossing over. If it takes him longer than a month, then it is probably my fault, and so it becomes my opportunity and duty to assess what I did wrong and to make the changes I need to ensure the next boy is more successful (I also meet next door to the 11 year-olds, and the boys are always free and eager to come to me for extra help even after they move on).
It is, however, essential for Webelos to engage with a Troop at least a few times each year, not only to meet a number of their requirements, but because that is the nature of the Webelos program - facilitating the transition to Boy Scouting, and ensuring that they cross over to a welcoming and active troop. If a Webelos leader doesn't keep that near the top of his priorities, he doesn't understand his full duties.
Mechanical hard drives have fairly strong magnets in them. It's probably more likely that you'd find a car when lost. Pull out the car speaker. A cell phone does have a battery and using that to make a magnet? With the head phone wires? (Hopefully not bluetooth) We're talking McGyver but the scouts might like it. Everyone I know that has a snowmobile knows how to pull the spark plug and start a fire with it. There are magnetic sensors in most cell phones. You just need the app to read them. I know, not much fun.
I am an electrical engineer. I would not worry much about the lead used in solder. Just don't eat anything. Most electronics should be safe from a chemical aspect. A shock hazard perhaps.
You are not going to find much in the way of magnets unless you have something with an actual coil speaker or motor. A modern day phone probably has a piezoelectric speaker. No magnetic material in those. Transformers will have some ferrous material in them that may have a small magnetic field to them.
Most ferrous material (iron) has a weak magnetic field. I have heard of inserting a needle through a cork and floating it on water to make a compass.
Many buttons, e.g. T.V. Remotes and older calculators, have lodestones in the plastic buttons. They were used to close circuits without worrying about narrow guides that would wear away after repeated use. Those little buggers have pretty weak fields, however, and make for terrible compasses.
Brian depending on where you live there are some great older boy camps around. My son and a friend went to Camp Rainey Mountain in Georgia last year and did a week of whitewater rafting camp. CMR shares the program with Camp Woodruff. Both are in northern Georgia not far from the Smokey Mountains. It was a 10 hour trip each way and they weren't the scouts from the furthest away. There are aquatic bases in a couple of the northeast states too. Just about every camp with older scout programs allow scouts to come as provisional campers (you don't have to go with your troop or own adult).
Here in the Great Lakes State, there are backpacking camps offered at Pictured Rocks National Lakeshore on Lake Superior, ATV camps, horse trek camps, canoeing and kayaking camps along the many rivers in the state. And sailing adventures in Straits of Mackinac area. Philmont has individual treks available for interested scouts. Sea Base has a match board for scouts that want to go but have no troop to go with. Not sure if Northern Tier has a similar thing.
What I'm telling you is you don't have to be stuck with your troop at the local minimalist summer camp. Read the ads in the back of Boys Life and research a place to go. That's how my boy found CMR. The sky's the limit.