First of all, hi there and many thanks for your enthusiasm. To answer your questions and comments, let's proceed in order:
- rather nice, isn't it?
- if you don't have any relevant skills, you roll d6 for your test. Usualy, your skill is a d8 or a d10 depending on the skills you get with your origin, your speciality and your skill increases.
- Homo machinus = cyborgs, robots, androids and all the rest; Homo goetes = sorcerers, wizards, fairies, atlanteans, and that kind of weird people; Homo vulgus = you and me, super olympic versions; Homo aberrans = metahumans, muties, aliens, etc.
- As I see it, the collars are primarily related to Adrenaline Rush. It's there to give a reason to this rule, and because it's the kind of thing you find in the stories of this genre. Then, if you look at one of the tables, there is indeed a possible twist to do with it (an antagonist or a representative of a third party pirates the necklaces). Finally, I think that some players will probably try to remove them. It's up to you to see how it can turn out ....