If you're doing research, look at the case of Wickard v. Filburn for what is considered the landmark case, and look at the Court Packing Bill for some background on how it came to pass. You might also want to read some of the opinions of Clarence Thomas on the subject, as sell as the writings of the founders with regard to the commerce clause, and commerce "among the several states". I can provide links if you wish.
As far as the question of the similarity an resultant jurisdiction and authority, AFAIK there are no federal laws against indecent exposure, it is considered a matter of state jurisdiction.
Oh baloney. You're just repeating what you've heard. Do some research for yourself, for once.
Congress was regulating commerce within the states as early as 1914, 20 years before FDR. I can provide you with a link to the Shreveport Rate Cases if you wish.