The first lady can’t get gifts
Just when you thought that if you were the President, assuming you were straight male, you would be able to find a loophole with gifts using your wife. Sorry, but neither you nor your wife can accept gifts, it’s just the law and you need to follow it or you’ll be in trouble.
You can not use the first lady as a gift receiver, the same rules still apply to her as they do to you. Nothing over a certain amount of money can be accepted or it is taken away and put into storage. They just don’t want anyone getting bribed while in the White House.