What I’ve gathered from the NoScript forum is that if presented in an Iframe, NoScript wouldn’t prevent .js-files from being downloaded to the cache, but it would prevent the scripts from being executed. I hope my understanding is correct.
Anyway, if the experts don’t think there is anymore to this even with my attempts at explaining my fears, I guess it can be considered resolved/closed until something more serious happens. My thanks to Asyn, DavidR and polonus for putting up with me.