I’ve only seen people choose Kraken for this mode and always win.
Kraken seems a bit broken in that mode to be honest due to his ability to siege the turrets and generators with little to no risk.
What Krakens I’ve beaten in Defend lost because they weren’t attacking the generator with their range - scared of losing armor to postshots.
In the past I’ve called for the buildings to be resistant to long-range attacks to force more interaction.
For Wraith, I suppose Decoy Supernova could be a good siege method.
Really though, I’d like to see Abduction buffed since I think it generally underpowered and I think it would be a fun and unique Defend playstyle.
For now though, be sure to duck out to regain armor whenever it is down - Wraith is great at disengaging.
Never tried Defend with a Wraith, so this is just theory, but I would say go in with the minions, target the turrets first, supernova/decoy, and always have armor up.
Not from experience, but I’m thinking abduction plus sneak-pounce to get 1 or 2 hunters downed, then do some damage and beat feet to armor back up. Rinse/repeat? Easier said than done, and not the play style I like, but it should work.
As a general rule the Monster should only go in with the minions, regardless of character.
Which is why I suggested it.