Witness gifts?

So we’re going to get married by courthouse elopement and we have our best friends (another engaged couple) as the witnesses. I wanted to give them a gift bag to say how much we appreciate them being there with us but I’m unsure of what to add in them?
I was thinking for him maybe some mini bottles of alcohol, thank you note, a tie and something else and for her, small bottle of champagne, thank you note, a necklace and Something else?
I thought about giving her a dress that I would like her to wear but I’m afraid if that would come across like “you can’t dress yourself”? (Which isn’t how I feel!)
help?