Cleric and Wizard.. Check.
Cat: I'll check the 'pre-roll' that comes with the game. If it's not appropriate, I'll roll one for you. (Good practice!)
I'm going to want to try and keep this "Fighter, cleric, wizard and rogue" (That's what this adventure is built around), but I'm happy for 'own rolled' characters. The latest Basic Rules are now available online (V2.0). Now with extra spells for wizards IIRC.
For rogues, backstab is now easier to implement. Significantly easier. Less faffing about with flanking or stealth or whatever.
Fighters are more consistent damage and increased likelyhood to hit. Also designed to be more 'party protector' (So giving disadvantage to enemies attacking an ally for example)