Thanks, this is some great advice. Basically, I'm getting my equipment prepped for this right now. I have a suction cup mount for my gopro as well, so I'm going to slap that on the wall and just keep it recording when there are kids in the area. This will give me some wide angle scene setting shots (in theory). I also have my 8-15, which, at 15 is a pretty useful lens, provided I don't pan much (as the panning motion on a fisheye can be a little disconcerting).
Seeing as I don't have ANY stabilization equipment, and just a ball head for my tripod, I was thinking of getting most of my shots from the tripod. Putting the camera on there, finding something interesting, framing it, hitting record, and not moving it. Then, when that action is finished, move the tripod, find something else, rinse and repeat.
I also put together a "string" stabilizer that I can step on to help somewhat stabilize high up and low down shots, but I was thinking that I should probably use the 24-105 for anything handheld since it's the only one with IS (other than the 70-200). Since I'll need to be focusing manually by physically turning the ring on the lens, and in my handheld tests where I was holding the 5d3 and the 70-200 in one hand while focusing in the other, it didn't seem all that stable, I wondered if I should use that combo solely on the tripod. Any thoughts about that?
Everyone has been really helpful. Thanks so much!
As for advice encouraging me to take it slow, I definitely intend to. In my experience, though the equipment doesn't make the "photographer/videographer/carpenter/etc", there's a reason why the pro "insert profession here" uses that equipment in the first place. Like learning anything new, I want to eliminate variables and focus on skills at the beginning, but the more I play with shooting video, the more I realize that holding the camera with my right hand, focusing by turning the ring with my left and trying to figure out if it's even IN focus without shooting the whole video magnified WHILE trying to keep it stable is freaking hard lol. Getting the footage more stable, and focusing with more accuracy and smoothness, especially with the assistance of the equipment that I already have, is my top priority.
As for things like the slider, If I do end up getting it, I won't be using it in time pressure situations in the beginning, but rather when I have time, an empty building (or a long rehearsal), where I can do a move 100 times, try it out, and if everything sucks, no one will even ask me about that footage. I've shot weddings and other "job" type things enough to know that if you're screwing around with equipment when the client is expecting you to be starting, you've got a PR problem on your hands.
The reason I mentioned the crane at the beginning as that it seemed to have interesting applications for both photo and video. Still, it doesn't fit my budget at the moment, and doesn't address my two immediate needs of "improved stability and focusing accuracy and smoothness" as well as some of the other equipment on my list.
Thanks again for the advice, and keep it coming. You guys have really been helpful, and I really appreciate it!