huehue Can't wait
I think you were already answered since I'm so slow to look at the forums. This is mostly explained in the rules but yes, you're assigned a random person and you will have to draw/write their gift for them. Additionally, someone is randomly assigned to you and will draw/write for your comic/novel.
Teecchnically the number of characters doesn't matter so long as the request is not something so complicated that it's like a commission. People should try their hardest to make a satisfying gift but it shouldn't require them to commit a lot of time for a free piece.
If someone gives a lot of characters, it's not likely they're asking you to draw all of them. Even if they are, you are not required to, especially if it's just too much work.