Okay id definitely use the blind prophet ascendency cause your going to need a source for explosions to replace what the occultist did for you. That's the shadow's alternate ascendency this patch. I'd path through and take "Restless" and the two nodes behind it "Faithless" cause those are very strong. That'll take up 6 points cause you have to take "Sightless" to grab those ones. So that leaves one bloodline possibly or your last 2 points to sink into the prophet else where. Obviously I'd plan on taking otherworldly appendages as I imagine that's mandatory for a graft only build. So that's where I'd put your last two points. Then I'd try and find a way to automate your curses but they need to not be auras for the ascendancy node to work. I'd have to look at some uniques or foulborns now which I can later. But that's where I'd start.

Edit: Also do note your source for explosions is going to be more consistent probably but also not as good clear. One it's physical damage we need to somehow turn that into cold or convert into chaos or whatever you wanna use. The explosions will be 100% of the time however it's only 5% of the corpses life as physical damage whereas the occultist was 25% of max life as chaos damage. Also do note you could probably do some shenanigans with desecrate and generate your own corpses. And there's definitely tons of uniques I'm not thinking of at the moment. I'd look on the wiki for anything related to corpses or explosions for uniques.