You have some very unusual selections and a nicely fluffy Haemonculus Coven already, so it's probably worth considering updating your army with some "usual suspects" from the top tier.
In other words, I'm advising you on the very best builds you can have for
DE in terms of gaming efficiency, not fluff or theme so much.
HQ: you need an Archon (
SF/CDs/
PGs + Either an Agoniser/pistol, or RJB Punisher/Tormentor Helm)
6 attacks on the charge, the CDs will be well worthwhile the foot archon can take advantage of the 12" assault drug (so he's technically *quicker* than a lord on jetbike!) while the Reaver archon kills
MeQ on 2+... This can be a Dracon in smaller games.
Incubi are expensive but are gfreat fun vs
MeQ. If I want Incubi I generally run a double
HQ so I wind up with an independent tooled Archon with the Shadowfield (either version), and a much tamer Dracon (Just give him agoniser, pistol, and grenades) to lead a squad of 5 or 6 Incubi in a raider.
Elite: Wyches, point for point one of the best assault units in the game and *ideal* for taking on an enemy character. Succubus with Agoniser, take 2 blasters and use a raider. Sometimes I take two squads - they atre simply awesome!
Taking a unit of those gives you access to the awesomely cost-efficient warp beast pack.
Troops: in fifth edition you need more than 2 troop squads... I typically aim for at least 5 troop squads in my
DE (and even for 1200 pt games!)
The big type your missing is a tooled raider squad: up to 10 warriors, splinter canoon,, blaster, Sybarite with Agoniser on a
DL Raider.
I'd have 2 like that and add a 2nd sniper squad (10 warriors, 2
DLs) to your army.
Reaver jetbikes - you need more... Im sure you already know how ridiculously fragile a 3 bike squad is, especially with all the upgrades adding much to it's cost. If I pay for a punisher succubus I want her to be used in more than one melee, so build then up to 6+ (and sometimes pair up with a similar Reaver Archon.)
Hellions are fun but are a specialist - you dont really need more interesting units like these if your looking for an efficient build.
Heavy:
You already have 1 Ravager, probably the enxt Heavy
Id suggest would be a 2nd Ravager. 1
DL and 2 Disintegrators is a perfectly acceptable build. I do advocate trialling Night shields for Ravagers - a friend swears by them (and he came 2nd in a
GT using
DE)
A Talos(or 2) is fun for the Haemonculus army particularly when you have a pair jumping out the webway portal!
Forget Scourges.
Choosing the units I outlined and being prepared to drop your Haemonculi, Grotesques, and Mandrakes, will see this nmove from a difficult to win with niche army it currently is to a fully fledged competitive tournament army with tools enough to meet the onslaught at a competitive tourney and succeed.
Good luck!