My daemon prince with iron arm and invisibility with stealth and shrouding will get a 2+ reroll, still need 6s to hit, and will only take one grounding test now if you put invis back.

And how are the bike squads getting a 2+ reroll without stealth and shrouding?

A quicker shortcut would be ban the grimoire if the screamer star is what you're worried about when you say deathstars, the seer counsel was cover based. But basically ban daemons I guess.