I'd dump the Scourges and Mandrakes. Whilst pretty model the mandrakes are a very poor option.
Drop the sybariter from the Warriors and make that two 5 man squads each with a blaster and mount both in duel splinter venoms. Get at least 1 preferably 2 (or even 3) Ravagers. Dump the blast pisotl from the Hekatrix you'll probably need fleet to make combat. The Reavers should just have a Clatrop and no other upgrades as soon as they slow down to shoot or assault they are dead.
Also why take the Hydra gauntlets when the razorflails do more damage? I never understand anyone that makes that choice?
So something like this still using the
BF as a core and Lelith as you seem to like her (personally I'd prefer an Archon):
Lelith 175
Haemonculi, Liquifier 60
5 Warriors, blaster, Venom with duel splinter cannons 125
5 Warriors, blaster, Venom with duel splinter cannons 125
8 Wyches, Haywire grenades, Hekatrix, Agoniser, Raider with Flickerfield 196
3 Reavers, cluster caltrops 86
Ravager, flickerfield 115
Ravager, flickerfield 115
Total 997
Wyches start with
FnP to help in that first assault. Reaver bomb around causing damage and annoyance. Warrtior squads can pop taransports and pump 12 Poision shots at 36" range each

. Ravagers take down armour, wyches and Lelith mop up, Haemmie stays in their raider and burns stuff (he's a 50% chance to go straight through power armour with his Liquifier Template

).