HQ options

Reading the rules it's not clear to me if I can use Drazar or the Yncarne as the HQ in a wych detachment (slashing impact, test of skill) instead of the sucubus, or they can just be included but I still need the sucubus to get the obsessions.

A Can Drazar lead a wych patrol (no sucubus)

B Can The Yncarne lead a wych patrol (no sucubus)

Yes and Yes

Yes they can. They just don't benefit from the obsession obviously, but you can indeed make a Cult detachment without a Succubus, or a Kabal without an Archon.

No... You still get the obsession. Why would not taking a succubus lose you the obsession?

He is saying that Drazar would obviously not get the obsession, because he is not <wych>. But the other <wych> units in the patrol still would.

What DingWop said. <Wych> units still get their obsession.

To take it one step further, you could technically make a detatchment with Drahzar, 3 units of mercenaries (Scourges, Incubi or Mandrakes), and not a single wych unit, and still get a Wych cult obsession bonus on the transports.

Ah, apologies then, misunderstanding your message