What are the best commanders for sieges?

[NewbieOne]

I'm mostly interested in:

1. Fastest winning the siege when you don't assault (raw martial skill? specific infantry troops?). I pay much attention to this because there are many situations I abstain from assaulting, mostly for roleplaying-related reasons (e.g. morale-based sieges when I fight somebody whose soldiers I really don't want to be killing).
2. Best for assault (probably much connected with specific proportions between various types of your infantry...).
3. Best overall.

Bonus question: Does cavalry affect anything? (Other than dying and especially knight retinues being expensive to replace.)

Please discuss. Thanks for participation.

 

[riknap]

high intrigue commanders get events that speed up the siege, IIRC

 

[unmerged(494787)]

I'm reasonably certain having the Holy Warrior trait speeds up assaults versus infidels. Of course, that's for assaults, not sieging it down the slow way.