The characters which have the feat Shield Brace should be able to equip both polearms or spears (Sized appropriately) and a light, heavy or tower shield (With which they have to be proficient).
Shield Brace's source: Armor Master's Handbook
I have attached a character with which you can test this.
CODE TEAM - is this hardcoded for the Weapons or can we control this from Data? I’m thinking Code has control of this currently because of the “magic” involved with weapons and hands…