Fanaticism works on: ?

[ogot]

Are Zeal's and Vengeance's attack speeds affected by Fanaticism? How about mercenary's/minions' attack speeds?

[Wyrm]

Are Zeal's and Vengeance's attack speeds affected by Fanaticism?  How about mercenary's/minions' attack speeds?

Yes and Yes. Helps anything that gets help from weapon speed (Frenzy, Strafe, etc.).

[Chameleon]

Yes and Yes. Helps anything that gets help from weapon speed (Frenzy, Strafe, etc.).

Well almost, it does not affect Whirlwind; only WeaponIAS does that.
And, it has reduced effectiveness for Wereform attack speeds.

[ogot]

And, it has reduced effectiveness for Wereform attack speeds.

Meaning less speed increased? Or the Wereform just doesn't want to attack faster?

[adeyke]

Wereforms have their own calculations wherein on-weapon IAS has more of an effect than other IAS.

One way to look at it is that the weapon IAS determines the fastest possible speed you can reach. Then other equipment IAS and skill IAS work towards this speed. What this means is that if you have a lot of equipment IAS or a high werewolf skill, you might already have the fastest possible speed for your current weapon, and fanaticism won't help at all. However, adding a Shael or a fervor jewel to your weapon might still help.

Refer to this calculator.