Can people lack a comparative advantage and a comparative disadvantage?
Comparative advantage doesn't work like that.

If person A's CA is cooking, person C has a comparative advantage in foraging. With B, C has a comparative advantage in cooking.

It's not possible to have a comparative advantage or comparative disadvantage in everything: If you were better at everything than someone else, you would have an absolute advantage. As soon as two people have different skills for anything, they have a comparative advantage of some kind.

It is possible for two people to have no comparative advantage/disadvantages whatsoever: If both people are exactly equal at everything they can do, then there is no comparative advantage or disadvantage between them at all.