It's now 2021, and after a couple of years of thinking, asking questions, and now building, I can answer these questions. I ran the 2019 season with the '08 CRG (GP Racing) Honda 80cc shifter with the Tulsa Kart Club at JRP speedway. Although I finished the season in 2nd place, that's not really all that impressive as I mostly showed up more than the 125cc guys. LOL. What I did learn is that 2-stroke engines are a pain in the but to jet and get started in cold weather.
As to class for this electric kart, I am aiming at 125cc TAG. Yes, approval is going to be an uphill battle to just run with them. I don't care about points and am requesting to run as "provisional" with the TAGs.
I'm also trying to get the SCCA to allow me to run in the Autocross events (again just for fun). They are still deciding on what is required to do so and I am actively trying to steer them the right direction.

And then there is drag racing. You show up, you pass a basic tech, you run. Easy peasy!
Anyhow, on to what I am now building based on that sprint kart chassis...
HV Swap-able Battery (first one): 42S10P Molicel P26A, 5.5Kwh nominal
LV Battery: 18v Makita tool battery
BMS: Orion2
Controller: Kelly KLS14401-8080IPS
Motor: DHX Machines Peregrine 60 (alpha testing), water cooled. Hawk 60 that it is based on is 75/120 Nm Torque cont/peak, 34/55 kW cont/peak
Safety wise, I am trying to follow the limited regulations the FIA released under their 2020 E-Karting platform (that they seemed to have dropped), as well as many of the FSAE rules. This is my main concentration - it must prove safe to the kart body more than anything. Many of the parts have been intentionally over-sized to make sure nothing bad will happen, especially in a full-on side hit. Just the battery and support structure have gone though several total re-designs to try and increase strength.
Here is a rendering of the current configuration I am building to showing the rear components:
Continued on new build thread:
EKartGo Project