WindRide, CloudTrapeze and MindHunt???

[Chazar]

I am wondering about the mechanics of these spells: WindRide, CloudTrapeze and MindHunt.

The settting: In an ongoing MP-game I am troubled by sneaking armies (mainly not-so-immortal-anymore vampires), which play hide&seek in my righteously newly acquired provinces. I chase them around but achieve nothing save instigating my own popluation.
Ok, I want to play the game for myself, so I dont want other hints how to deal with those hideous thugs, but I wonder why the methods employed failed so far:

-WindRide: In its description it says that EarthMages and big creatures are likely to be impossible to lift, yet VampireLords are size 2 and have no knowledge in earth magic, but still wont get wind-ridden after they have revealed themselves by attacking. Why? I think my spells should come first before they are able to hide and sneak away again? Right or wrong?

Searching the forum, I have found someone mentioning that Etherealness is also good for stopping WindRide? Why? Or how could I know this, save from the flavour of Etherealness? Are they immune or is it just unlikely? (I tried 8 times so far. This cost more than its worth!) Do those Magic Penetration Amulets that I already use affect the chances for these ritual-spells at all?
Also, what are the rough chances for WindRide with respect to Size and EarthMagic? (e.g. is it already almost hopeless to target size 4 creatures?, etc.)

-CloudTrapeze: CloudTrapezing onto the sneaking thugs, just after they unhid themselves by attacking, didnt work either, for the thugs were ordered to retreat. What I wonder though is what happens to those retreating thugs orders? They retreat during the magic-phase, so would they carry out their orders after the retreat if they can? Are they even capable of still moving, provided that their former destination is still within reach?
(Btw, just for completemess anout these spells: I was also reminded that CloudTrapezing is good to reinforce besieged forces, but bad for attacking siegers... )

-MindHunt: Are mindless creatures immune to MindHunt? Or is the only defense an astral mage?