Far as I know nothing in champ directly effects them. Just stack max magicka.

They should benefit from spell crit though

The Twilight is not affected by any CP, thus not a good dedicated damage source.
The familiars AoE pulse is affected by elemental expert, thaumaturge, spell erosion, elfborn.

Use daedric prey in ur rotation. Use necropotence. Pump up tharmaturge and a little into master at arms to buff direct damage attacks because the scamp does damage with an aoe direct damage pulse with a stun if u use the volatile familiar. Twighlight does a single direct damage light attack every few seconds, use the healing twighlight and let it passively attack. They do a single direct damage attack similar to a stave light attack. Pets scale off of ur own damage and penetration values...and max magicka