Hey Kim I've used both Yvraine and the Visarch extensively in games. You have to field at least ONE of the Triumvirate to field a Ynnari force per the FAQ and Yvraine is probably the most obvious choice. She is absolutley awesome on the tabletop. She's really cheap, powerful in combat and is one of the big heavy hitters in the psychic phase which is her tabletop speciality. The Visarch is waaaaay overcosted but with the invuln save granted him via FAQ he's like a slightly beefed up Y'riel in terms of attacks and defense particularly when given the warlord trait that allows him to ignore wounds + mortal wounds on a 6.
I've no experience with the Yncarne but I've heard good things. Very strong in combat and the psychic phase, but a bit tricky to use, especially since the Ynnari nerf/faq.
In support of them Wraithguard with D-Scythes in Wave Serpents are an absolute essential (or perhaps webway striking if you have a CWE detachment in support). They are the #1 choice for Soulburst with shooting and would pair Yvraine with them everytime. But since the FAQ you can only choose to shoot once via soulburst, so I'd round out the soulburst goodness with Howling Banshees as they can make contact very, very easily with Warlock support to make some first turn charges and hopefully generate a 2nd round of fighting via Soulbursts. You could alternatley use Incubi or perhaps pair them together.
As for troops, I'd probably get a cheap battalion going with Dark Eldar warriors in Venoms and then just lean heavy on the boosted CWE codex Aspect Warriors.
Ynnari have definitley been nerfed, but dont believe the hype. They are still very strong especially if they can use Craftworld Stratagems.