Rescue that can play half? That's... actually a cool idea. But it depends on how Team works (either one alone or all in effect) and if the staff would consider non-Leader Team effects.
I would prefer Team: -3 Opp Attack, Min 5, just to try an make it less of a Rescue-ripoff.
Important question: What happens when faced with SoB? Does your card only lose it's effect, but keep the others? That would make it's bonus rather resistant to Piranas and Nightmare.
Vanity: That's a pretty cool idea... I think it would have to be worded as "Support: Enhance Team Bonus +3 attack" So that if a card is up against something with SoB, that additional +6 is shut down as well -- if nothing could mitigate it, it would definitely be OP...
This might give a little bit of life to old attack manip clan cards that just don't have what it takes to hit anymore. Ficcanaso, Milovan, etc become very ELO-worthy cards as long as you draw them in a 2/2 hand. Sakrohm's SoB/CoB lineup becomes very dangerous as well. I worry a bit about certain cards becoming way too hard to stop, however, strong SoB and CoB setups make it so that a deck like that is not exactly risk-free to run... And of course, a 3/1 hand would be at a bigger disadvantage than usual, as well.
I would imagine that in case of a Team:bonus being cancelled it would mean that the bonus would be stopped for good. So in the case of Team: -3 Opp Attack, Min 5 in mono. First round, the card would still get -9 opp attack from the other cards, if that card's bonus would be cancelled. And the remaining cards would also get the -9, because the 4th one was cancelled.
What about a protection: attack bonus? They would still be affected by power and damage manipulation, but they'd be able to go toe to toe with the Uppers and Montanas.
As for a theme, how about a Bizarro clan? Take some of the weakest cards form the other clans (like Bob Joby) and create a bizarro version that's the complete opposite and with competent stats and abilities.
As a bonus, Copy: Opp Ability has too many flaws to work.
1. Balancing a card's stats and ability would be insanely difficult with that bonus.
2. Some card's abilities are useless against themselves. Try using Spiaghi's DR against him or Tobbie's PR.
3. Some cards don't have abilities or have abilities like Backlash.
4. Courage, Confidence, and Revenge will only be usable by the opponent; unless they play really badly, you're not going to copy those on the right turn.
5. Stop would be impossible to copy, barring strange card design. As far as I'm aware, only using CoA as an Ability against Mini Mund has even a chance of working.
6. Protection would be useless in the vast majority of situations.
7. If you're not playing Mono, Support is less effective.
8. Leaders can't be copied, probably. I base this assumption on their immunity to SoA and their functions.
9. Some abilities (like Bodenpower) are weak to work with a strong bonus or stats.
10. Nightmare and Piranas enviable abilities are protected by their bonus.
CoA would be an interesting Ability, but as a Bonus, it's just too random and weak. It would be a struggle to use, fight, or balance cards that are that opponent-dependant.
CoB would be easier on all fronts. It would create mirror-matches that weren't exactly "mirrors" and could be balanced similarly to Piranas and Nightmare (strongest against bonus-reliant clans).
Heal 2, Max 10 sounds fair to me. It would function similar to Freaks.