1) Yes, that's correct. You are guaranteed one single gift, to match one thing you requested. You are only required to create for one of your recipient's requests.
2) You can post the assignments and treats whenever! The collection is currently unrevealed and anonymous, so it doesn't matter when before the deadline you post, nobody will see what you created until the correct time. Just be sure you click "fulfill assignment" so it'll definitely be marked as a gift to your recipient and will be put into the correct collection.
Re: First Time Questions
1) Yes, that's correct. You are guaranteed one single gift, to match one thing you requested. You are only required to create for one of your recipient's requests.
2) You can post the assignments and treats whenever! The collection is currently unrevealed and anonymous, so it doesn't matter when before the deadline you post, nobody will see what you created until the correct time. Just be sure you click "fulfill assignment" so it'll definitely be marked as a gift to your recipient and will be put into the correct collection.