First, a big THANK YOU
to all the participants thus far.
An update for those that are interested. I contacted Jason at E-BikeKit and he invited me down (~40miles away) to check out the proto build they did for Worksman. Those of you that followed the original post saw that they are coming out with an E-TrikeKit and it is a 500W motor. The proto build is the set up that the Worksman Lighting E-Trike will be. I don't think the Worksman posting accurately reflects the kit. It's a black, front-wheel direct drive. The kits were crafted so that it looked incredibly easy to install them. No flying leads, just keyed plugs.
As it turns out, I bought the proto because I believed it could be adjusted to work for my daughter, and here was a near perfect solution!
So, Jason was incredibly helpful, I learned a lot about the technology and the set up. He gave me more than two hours of his time. I test rode/drove the prototype (my first e-bike experience!), it hadn't yet been speed limited! We took apart the controller to see how it might be speed limited. My daughter's situation is unique because she weighs so little (54# soaking wet). So, we'll probably do something simple in line from the throttle. They did not have any of the speed controllers that posters mentioned. But, it might be nice to have something to give speed back if mom or dad ever wants to ride!
I'll get pics of her riding after I take care of the speed. I don't have much spare time to work on it. She's seen it and is excited. There is some blackmail going on in that if she doesn't pedal, I'll turn off the battery!
Finally, I need a solution to add more/easier braking to the bike. The original Worksman had two hand brakes. One was a front caliper, the other was a front drum(?). So, now there is only the front caliper and there are two concerns. 1) it takes a LOT of effort to stop the bike 2) it's hard for her small hand to squeeze with any amount of pressure.
So, experts, what can I add? I believe the fittings are on the motor for a brake disk, but I don't think the fork has the needed clearance. Can I get a fork with with the needed mounting points for the disk caliper that is wide enough for the wheel with the motor? I have an extra hand brake that is only serving as an e-brake. Should I change out the gear to a coaster brake? It's something she knows how to do, but would still take a heck of a lot of pressure to stop. And, I'd want to add the cutout components discussed before. What about rear disk brakes? Is that even possible (within reason)?
Let me know if you need pics of the fork to assess braking options.
Thank you to all the original posters for your great ideas. Thank you to Jason and E-BikeKit for his time and expertise.