I’m fairly new to Halion, so please forgive my ignorance here. I tried to find ways to access the samples, or import them into Halion but I wasn’t successful. I could only find this thread regarding Halion Library Manager, and I have this problem of the option button not showing up:
I’m using Halion 6, but I have the full Absolute 3.
Neo Soul Keys was once offered as a Halion expansion sold by Steinberg (which came with a Halion-based standalone version), but this version has been discontinued.
The current version from the link you posted uses a custom engine that’s not compatible with any other sampler.
If you would like to see a new Halion version of Neo Soul Keys, consider asking Gospel Musicians about it. The Halion engine is much more open than it used to be 5 years ago, so they could probably make an updated Halion version if they feel like it.