Ah, Hanso Charisma Charms are not worth hardly anything anymore, they were a plot prize originally. They block all darkness and have a 10-icon attack. So they are a small step down from The Mystical Tablet. You don't need them.
Sure! During battle, open and check in the combat log, it'll be on the left side, under your pet, it will say the damage you take, and that includes the icon types.
Though you for the 1p opponents you can also know what they use by checking out the 1-player profiles of Secret Battledome Challengers. TDN has these here. Under the heading Active Challengers.
https://thedailyneopets.com/battledome/secret-challengers
Click the challenger you wish you fight and you will see their stats and equipment. Click on their equipment and you will be taken to that item's item database entry with it's stats, what types of icons and how many of each icon it does. As well as special effects that might be known. If you know what icon types might be prevalent in your opponent's arsenal, then you can plan the proper defensive gear for it if you need it.
Whenever the new plot's battle phase starts, that's something we at TDN will be figuring out. What the new opponent(s)' weapons are and if there are any new ones, what they do. Then we will create a new entry for them in their own plot section. So when the battles start, please stay tuned as we will be working to figure out the info and get it up asap.