That’s a big party to try to fit into in the first place. Being an only sometimes character makes it a bit harder as well.

So you’ve got a lot of Charisma and Intelligence in that party, so they don’t really need more of that. The role I do see that the party doesn’t have is a true sneaky type, unless one of the Bards fills this role. But you said that you like to cast spells, which means that most rogues are out except for AT, but your party has plenty of Int already.

So, to fill the role of a wanderer, I’m going to suggest either a pure Ranger, or a multiclass Ranger/Rogue depending on your level. Ranger would let you have some spellcasting, and would make sense to be able to show up where ever the party is at the time.