Multiple % to X on Hit?

[Vanadin]

Right now, I have a belt with ~4% chance to Freeze on Hit, and an amulet with 4% chance to Blind on Hit.

What I'm wondering is this:
(1) Is it one effect per hit per monster, or can they stack? [I would imagine they can't, since some seem mutually incompatible, such as Freeze and Fear.]
(2) If it is one per hit, what's the order in which they're tested? Is it by item (e.g., D3 tests helms, then ammys, etc.)/effect (first Freeze, then Stun, etc.)?
(3) My primary character is a DH who uses Jagged Spikes caltrops. Do those test only with the first hit, or on every single tick?

[lanceuppercut]

I'd like to know too but might be worth asking the WD's as they have a CC based build going on so maybe someone there knows a bit more on the CC side of things?