Can you use a treble hook? What kind of string and hooks do you recommend? Thanks!

Treble hooks can be useful for holding your bait in place securely. However, you need to know that not all locations allow you to use them. You don’t want to get yourself into trouble for using them in the wrong locations. You need to find out the fishing details for a given state or location before you assume that you can use them. Keep some in your tackle though so that if it is legal and you have a need for them, they are on hand. I tend to stick to the smaller treble hooks. They are easy to work with and they are more powerful than they look.
I recommend using line that is very strong for the type of fishing you are going to do. You don’t want to save a small amount of money on the line and then it breaks as you are reeling in the fish you have caught.