Our saga continues with my son. But I think we are narrowing in on what works best for him.
We've tried the Bauer Concept 3 splash guard, CCM Game On mask, and an UnderArmor sports mask. All with a Bauer Concept 3 bubble.
For him, the best results are the UA mask.
The splash guard fogged on him and made the visor fog more.
The CCM mask felt too restrictive (maybe we needed to experiment a bit with adjustments, but didn't)
The UA doesn't cause extra fogging and felt less restrictive. He is also used to it, as he's been wearing them for dryland, warm ups, and with his trainer. So he knows what to expect when he is putting effort in with the mask on.
Given some states are now requiring a mask while on ice (we've been proactive in reducing his risk of exposure), I am going to pick up a few more UA masks for him so he can always have a fresh dry one, as he does soak them while playing or working out.