A caster is never irrelevant. A level 2 wizard can provide Shield for +4 deflection AC. That's huge during a NCE, and that's just one spell. Get one level under your belt (and you can do that RPing in an inn) and you'll have access to Invisibility, and be able to slip past most things in the area. A level 2 cleric can provide Shield of Faith (which isn't as good as Shield, but is something), Bless, Magic Weapon, the much under-used Remove Fear, or simple healing.
I'll grant the level 2 rogue is going to suffer a bit against all those undead, but they still have their role; to paraphrase a saying, they don't need to be stealthy enough to avoid being spotted by the enemy, they just need to be stealthier than the paladin.
It just feels like a very narrow interest that you're actually defending here, and one I feel that doesn't gel with the main principle of NCE.