OP, I like the drivetrain. My only issue is with all the L-brackets, which are always kind of finicky to get to fit tightly. You might want to look into tab-and-slot connections to make sure everything fits well. @Allison_K might have some pictures of fitting a captive nut into into a tab and slot design, which is cool.
This could be a minor complaint, but if you look at this design from the top, it’s made of rectangles. Rectangles are easy to make, but not particularly rigid. The bellypan is doing some good work to keep the big center rectangle in shape, but the outer rectangles that make up the wheel wells aren’t all that well supported, and might be susceptible to deforming like this:
If you attach those two plates with a flat plane (tab & slot attachment?), you can keep that assembly as rigid as the center part is. (As a bonus, it’ll also help to fix @ngreen’s concern with the sheet metal bends).
@oblarg and Co, this conversation is technically interesting, but only tangentially relevant to OP’s drivetrain. Maybe bring it to a new thread?