She will make a lot of appearances on my skirmish team.  Even if she isn't tier 1, she'll be a lot of fun.

As for her effectiveness, I am not sure she will not be tier 1.Â

Her hps will be 45.  Bank on it.  That is what the RPG version has, and they only change that when there is a good reason.  Couatl, Ghaele, etc... have their RPG hps...  I'd be dumbfounded if it were less.

What does that mean?  Let'a compare her to the Couatl when assasseing how she responds to being slapped around by your opponent:

If you're being hit for 30, both creatures morale check after 1 hit, and die after 2.
If you're being hit for 25, the Lilliend routes after 1 hit and dies after the second, while the Couatl can take 1 more hit before each threshold.
If you're being hit for 20, both creatures morale check after 2 hits and die after 3.
If you're being hit for 15, both creatures morale after 2, the Lilliend dies after 3 hits, and the couatl dies after 4 hits.
If you're being hit for 10, both creatures morale check after 3 hits, the Lilliend dies after 5 hits and the COuatl dies after 6 hits.

They're fairly similar, with only minor advantages for the Couatl.  The 65 hp threshold is a big threshold - but falling short of it by 5 or 15 points isn't that different.

So, then we look at her abilities:

Beguile is a huge ability.  If it works, you can a.) set the creature up to be killed off by all of your heavy hitters, b.) be forced to use up a powerful ability to the detriment of your foe, c.) move a powerful opponent someplace where he'll be useless for at least 1 round, or d.) a lot of other sneaky things.  It can put your entire enemy force out of command.  It can make a Chraal use up the cone of cold on the HBG and open a hole to let your other bashers get at the HBG.  It can force an HGB to wail on the other HGB before moving someplace where he can be kept out of combat for a good amount of time.  Think of combining this ability with a map slopes... Nasty.  Think of it this way: You lose the attack portion of your round, and you can set back your opponent at least an entire rounds worth of benefit... Nasty.

Remove fear means that you can live without a commander in a band with one or two creatures that need to make morale saves.  If CG ever gets a great titan figure, I can imagine running it without a commander and using the lilliend to save it from a failed morale save... And this spell has other uses.  With those Aura of Fear 5 abilities that epic dragons have, this creature can keep a lot of creatures in the game despie the difficulty of the morale check.  Finally, the creature in question doesn't lose an action.  It might even be able to chrage right back and nail the guy that sent him packing in the prior activation.  If you set up the routing path right, the use of this spell can turn a failed morale check into a benefit that allows the creature in question to move to a better target and get there a round faster... which can be huge for slow pieces.

I don't think I even need to mention how cool flight 10 will be.  That is a pretty mobile piece...

Her attack, despite the 15 damage, will likely be lacking.  It might exceed +11/+6 on the attack bonus, but I think that will likely be the bonus.  That isn't terribly great, but it is easier for flying creatures to charge/and or flank... meaning that she can likely get to a +13 or +15 on an attack which is respectable.  Due to the fragile nature, you wouldn't want to move her in until you're dropping the final blows... but she can be used to drop in that final blow on a foe that is immune to the beguile....