An Epirb is a battery operated device that in case of sinking (which Triumphs should not do) will send a signal via satellite to the Coast Guard with your lat/long coordinates so you can get plucked out of the deep blue. Here's a link to one company that supplies them, I'm sure there are others:
http://www.landfallnavigation.com/epirb.html
I carry a gaff, but have never had need for it. I carry a big dip net that I picked up at Bass Pro that has worked fine so far. A gaff would come in handy on a legal cobia and kingfish that couldn't be brought in any other way. You can pick one up in either a short handle, or long handle variety.
What's the plastic bucket for?
As for the bucket, while it is not a necessity for me, it is for my wife and daughters. The front mega hold can turn into a "ladies room" and the bucket into the plastic throne.
Better to ask questions now than to realize 20 miles out that you should have asked something. We've all been there...and still are asking questions.