My mom can remember agri inspections on the Ohio-West Virginia border in the mid-Sixties. She knew a little girl who delighted in saying to the inspectors with a big grin, “No bugs today!”
Yep, this.
So unless you plan on traveling with Snakes or smuggling Banana Polka plants (or Pakalolo). You shoud be ok.
Well, you should jknow by now what they don’t want on their plane! 
No, I don’t read that as foreigners flying to Hawaii from the mainland US. It looks like it’s saying if you’re a foreigner entering Hawaii from outside the US – meaning if your point of entry into the US is Hawaii – then you’ll need to show a passport and maybe a visa when you go through Immigration. They still don’t have to go through Immigration again if they’re flying from another US state.
One quick question I have a friend who is a us pr card holder and he is in dominican republic can he use the ferry from dominican republic to puerto rico? And do you have to go through immigation in puerto rico?