It’s not Ultimate cheese if you’re using a Champion
I would argue that Lancelot is the most broken companion after you get teleport setup going.
For ultimate cheese party you probably can skip Mordred and go for 1 sage (inspire+buff dmg + general support), 2 vanguards and lancelot. For bosses you probably need a tank so swapping 1 vanguard for Mordred is probably a good idea. On the other hand having multiple cheese characters that rely on dmg each kill might be a bad idea since they eat away others damage potential. All you need (at least on hard difficulty) is 1 dps character with ap each kill + dmg each kill bullshit build. So having 2-3 support characters and 1 dps char might be best for random missions in general (3 chars with inspire / hexes / dmg buff and 1 dps).
So:
Galahad for divine favour
Guinevere+Isolde for dmg buff/inspire
and 1 dps char vanguard or lancelot
And the game is great one of the better games I have played in few years. If there was not chalice 2 it could be my game of the year so far.