Sorry I wasn't about to catch you! Here are my thoughts =)
1. I like that idea. Gives him the brevity and brawn of his father.
2. & 3. They can be romantically involved or the platonic partners, either way is great! I know there will be a strong attraction, if the second route, just because they are so like minded and it's hard to find someone else who thinks the same. Especially when that particular mind is so very odd. She has poison generation, so I'm thinking she's been killing for a while. Was probably wronged by someone as a child and has since been out to get them. Probably a hero, so that would make her a threat. Wants that hero to unmask himself and everything. So she's probably killed before. Maybe they were both after the same person, he to steal his identity and she to kill, learned "you scratch my back, I'll scratch yours" was a good route for this particular target and then he was lying dead, with no records to identify him so Fortis could get away with it. Then maybe something in her made him come back to find her?