For a) you are clearly right. See the FAQ:
S&S FAQ wrote:
While you are attempting a check against such a card that you did not encounter, powers that would apply to the character who encountered it apply to you instead.
For b) I'm puzzled. I always assumed it would be 10 if the character's strength die was a d10. But now that you asked, it makes more sense to roll it. I'm surprised I don't find this mentioned on the Paizo site.