Lol ... Trump can no more waive "Executive Privilege" than I can. The man is utterly delusional. This is just Trump trying to act like he’s in charge of his deluded minions. He knows Bannon is going to do this, so he is trying to spin it in a way to save face. “Yeah, I totally told him to do it, so he can prove how deceitful this criminal committee is being”
The Committee has no reason to allow any sort of live testimony. Everything about this is planned. And the only thing that Trump cultists gain by insisting on going live is the ability to try and hijack the hearings. If it’s actually someone wanting to confess, they’ll gladly do so behind closed doors to be rebroadcast later. And if they’re ratting someone out, they’ll want to do it behind closed doors regardless.