Some great ideas!!
A word of caution re the ones directly connected to Cancer. I'd think long and hard before bringing them into the "games". This is NOT a game to the person who has to deal with it and I know I were in the position, I would NOT be amused in the least if that was the fun of the afternoon.
The party you are planning is a great and fun idea for all to help your friend during a difficult time. I know the intent is good, and I just don't want to see the kindness and warmth of your idea spoiled. It could happen so easily and yet, you can have a great time with all, with wonderful memories created, that will help your friend during the most difficult of times.
As another thought ... how about blocks for a signature quilt being there for everyone to sign? And then make it up for a gift for your friend after. Or perhaps do them on the "sly" and keep it for a surprise for her later.