I like your concept. Since you are going pact of the chain, we can dump the Blade Pact invocations. The warring dual nature of Shadow and Light between Hexblade and Divine Soul is fun. Since you don't want to be leaning the trickster route maybe focus on searching out lost souls that are trapped in the Shadowfell instead of heading to their Outer Plane resting place. Maybe you will help them to their final destination or maybe you are trying to trap them to give power to the Raven Queen?
Bouncing off your raven feather idea, maybe take Cloak of Flies and reskin it as a shroud of ravens feathers or even a murder of crows. Ghostly Gaze would play up your ties to the realm of death, so can Shroud of Shadow.
If you are only dipping into warlock, it will change recommendations. Devil's Sight is a fantastic ability, but it is a double-edged sword when party members can't see in the same darkness.
Ultimately, pick a theme for your character. Which side of their heritage will they favor? Then think of how they will advance their calling. Pick the invocations that fit. You can already avoid trickster invocations and pact of the blade invocations, so there isn't a ton for you to choose from especially if you take the pact of the Chain options. Are you using Eldritch blast? There are a lot of options there too.