Um... if you're going battle cleric, to be honest, you're probably better off going two-handed and grabbing a greataxe or a greatsword or something.

Considering the myriad of buffs that Clerics get, you might not even need proficiency, though a level in fighter wouldn't hurt. Or going Half Elf instead and taking Fighter Dilly.

Also, I think the completionist description is a description goof - the person who wrote it probably forgot multiclassing even existed. A simple "You reached the level cap with every class!" would probably be vague enough to satisfy every condition.

Oh, and if you're going to melee, you want Power Attack.