Tha article is about banning the conversion of street vehicles to race only - hence to control or limits on emission controls. It has no implications, as written, for street vehicles that are already regulated for emissions. This has nothing to do with safety. The EPA doesn't regulate that. They regulate the emissions and that is what they are doing here. You can still have a street car, subject to regular emission standards, and modify within those rules.
I haven't tried it in clear plastic. Judging by the perfor ance on regular plastic, if your window glass fit well, I think it would hold. If you had to clamp or tape your glass in and the joint would be under pressure, I don't know. Maybe, maybe not. It does help if you rough up the surface, but that might not be easy on clear parts. Bondic does work for quick filling of holes etc - just fill, light, repeat.
Try the smaller can of Duplicolor. It's light gray, thin, smooth, and doesn't seem to be as hot as the big dark gray can. I used to use he dark gray a lot, now I've switched to the slightly more expensive small can like this:
Pinning parts is great advice. What type of glue are you using? I use CA glue 90% of the time - you only need a small amount, it dries fast, and can fill small gaps on joints, etc. I use the medium viscosity type - thin runs too much for my preference. I also regularly use a "kicker" to instantly dry the glue - just make sure you have things lined up correctly. For "glass", tape the parts in place and then use a clear glue around the edges - glue, like Testors clear parts glue, is pretty thin, so it wicks between parts well, and dries clear. Try to find a spot to glue that won't be readily visible. Paint and touch up after gluing is important. All modelers make mistakes - fixing those mistakes makes you a better modeler.
Oh, nice. Probably be a great little kit - thier Subaru 360 is and I assume this will follow suit... The Japanese market seems 180 degrees from the US - and I love it! Base model 4 door cars, tiny KEI cars...imagine if Revell announced a 1980 Plymouth Volare four door and a 1985 Oldsmobile Firenza...