Looking at the new Craftworld Eldar book and there appears to be several strong combinations between them and allied Harlequins and Dark Eldar.
Add to all this Jain Zar and you get a -1WS/Initiative bubble for all enemies within 6″ of her. That means that the entire squad should be hitting on 3+s (and likely being hit on 5+s, for most enemies) in assault and also striking before their enemies in combat. Additionally, due to her Banshee mask, enemy units cannot overwatch on the squad as it charges in (looking at you here, Tau). Finally, Jain Zar has Fear and her “War Shout” ability, which makes enemy locked in close combat with her have -2Ld. Combined with the “Freakish Spectacle” rule of the Haemonculus to net -3 Ld for the enemy (so at best they are Ld7), this means that if the Squad wins combat, as it is likely to do, the enemy is very likely to break and, with its initiative reduced by -5, basically automatically lose the Sweeping Advance roll off and be wiped out (unless they are Space Marines and have ATSKNF, of course).
Shooting-wise, this squad put out 5 x S3 AP (variable) Templates a turn, plus Jain Zar’s 4 x S4 AP2 Triskele shots (fire at BS7, so very likely to hit). Combined this should do great damage against hordes and even do well against heavy infantry (especially if the Liquifier guns get a low AP value).
Combat-wise, on the charge the squad puts out 21 x Flesh Gauntlet attacks (Poison 4+, with 6 to Wound getting Instant Death), most of which are S5, so good chance for re-rolls to wound against most targets due to Poison rules. Add into this Jain Zar’s 5 x S4 AP2 Shred attacks on the charge, all at WS7 and I7, and you have some brutal close combat output. Should you have to challenge an enemy (or be challenged), Jain Zar can “neutralize” one of their close combat weapons per turn by giving up one of her attacks… i.e. she can make an enemy “lose” his Thunder Hammer or Relic weapon while in the challenge while still having 4 x S4 AP2 Shred attacks a turn herself in the challenge. Translation: DO NOT get into a challenge with Jain Zar!
Since the whole unit can ride in the Raider, they should be able to rapidly move accross the board (12″ move + 24″ Flat Out with Aeither sails upgrade), survive enemy shooting (Jink + Night Shields gets you a 3+ cover save), and then set up a turn 2 charge (since the vehicle is open-topped) by Jain Zar and her Frankenstein bodyguards. Finally, with good use of Look Out, Sir! and model positioning, you can maximizie the survivability of this unit against shooting… Jain Zar can “tank” AP3 and below shots with her 2+ Phoenix Armor while the Grotesques, with their T5, FNP, and 3W each can “tank” torrent of fire shooting that might normally be a threat to Jain Zar and the Hamonculus.
Overall, I think this is a very affordable (points-wise), survivable, and deadly unit that can be quite effective in competitive games.