Combined arms combat question

Hi

I have these questions

a) In a  CAC (combined arm combat) that includes Cavalry and artillery, if there s a cavalry bonus attack, ART dice are added to the CAV bonus attack?

b) In case of a Lancer CAV as a part of a CAC, do lancer re roll dice in case of a cavalry bonus attack or only in original attack?

Pd. Sorry if this has been asked before
 

a) artillery could be added to a bonus attack, but artillery can attack only once. So if the artillery combined with the original attack, the same artillery could not combine with the bonus attack (but fresh artillery could!)

b) Lancers reroll flags when allowed for any attack, original and bonus

Thanks for your answer