Valiant Hero Bonding is a bold move. There are a lot of Valiant heroes, from Charos to Sam Brown. Bonding with a ranged hero *and* a number of beatsticks is something few squads get to do. Between Intimidating and Bull-Wark increasing their survivability quite a bit and such potent bonding options I would imagine you have the Minoan Guard somewhat underpriced.
Do you want to have so many powers that make attackers or defenders roll more or less dice packed on to just two cards? I like Brorok but I ultimately feel that you could present a more thematic (and possibly simpler) card for the Minoan Guard. I would start by just dropping Bull-Wark altogether.
I wouldn't call that a "bonding chain," really. I also don't think it will turn any heads in a negative way unless you try to submit them to the SoV (and I imagine the figure availability is not there).
I am not 100% sure what you mean for Bull Headed to do, but if you mean what I think you do, you might perhaps borrow wording from the
VC's Varkaanan Swiftfangs.
For Sound the Charge, why not wording closer to Siege and Evar Scarcarver "After taking a turn with Brorok you may reveal the 'X' Order Marker on Brork's army card to..."
Intimidating functions similarly to the
Goblin Cutters's Mob Attack, but the wording is again pretty different. On the other hand, aping their wording could be tricky since Intimidating takes place when attacking AND when defending. Bull-Wark also seems very similar to the
Roman Legionnaires's Shield Wall (minus the restriction, of course) but the wording is fairly different.