Is it an airdrop or a different contract I need?

Hi all, I made my first Manifold ERC 721 Contract last week. I minted 10 NFTs for a collection - each one different. Now I want to prepare a gift for those who mint but I’m so new I don’t know the method for this. I have an 11th NFT that is the gift. It should go to 12 at most (because 2 people helped me get this far and I want to give 2 to them), meaning that everyone who mints one gets that 11th NFT. Someone told me if I add it to the collection it will affect floor price, which I don’t want.

How do I do this? Do I make a new contract for 1155 and mint the gift to that or skip minting and do airdrop? Technically speaking I’ve read a lot through your documentation but I just cannot understand the airdrop. There was another thread here that mentioned I could send folks to a claim page so they could claim it themselves. I read that you could program the ERC 721 contract to have unlockable content. Does that mean I can embed a second NFT inside each one? Thanks in advance.