No 'blanket" all-purpose answer can be given to this. Depending on many factors it may sometimes be lawful while in other areas and at other times, unlawful.
probably, yes
Illegal.
Depends on the state, but mostly yes.
No it is not illegal to drive with sandals on in Navada.
Yes, it is illegal to drive with expired inspection stickers.
Yes, it is illegal to drive in flip flops in Louisiana.
Yes, it is illegal to text and drive in North Carolina.
not illegal, just stupid
So long as you don't drive the car w/ the bogus plates you are fine. If you drive the other car and get caught; expect an impound and a fraud charge.
No, unless you're using profanity or threats that bother someone who hears it. Then, depending on your state's laws, it might be.
Yes it is illegal
Yes, it is always illegal to drive while intoxicated, no matter where you are. However, it is rarely illegal to drink and drive unless impaired.