As long as it does not obscure your lights or license plate you can drive with your tailgate down.
In a word: no.
It depends how small the children are, if they are under a foot and a half then it is illegal.
yes it is legal to drive your truck in Texas with the tailgate down.
Yes.
yes
Yes, it is legal to drive barefoot in Tennessee. There is no specific law that prohibits driving barefoot in the state. However, it is recommended to wear appropriate footwear while driving for safety reasons.
Binman drive garbage trucks.
Trucks are used for carrying supplies and to just drive.
tailgate
Yes -- either that or there are an awful lot of trucks breaking the law and getting away with it. Trucks can't drive on are parkways but expressways are fine.
In the US at least half the people drive trucks, so some of them must own logging companies. Owners of very small logging companies might actually drive trucks at work.