How to create a custom Mii fighter character for Smash Bros Ultimate? [closed]

I want to create a custom Mii fighter character for my boyfriends birthday coming up. I've done some research and it seems there are a couple ways to do this - however I am looking to get advice because ideally I would like this to be a surprise, but most articles seem to indicate that I need to build this using his Nintendo Switch console, or in his account. I have a few questions about this actually, and I know most of these groups like each question to be posted in its own thread, so I apologize, and will try to group them by specific topic.

1. I heard that in order to even use the Mii fighter characters, you need to unlock them through something called "story-mode"? I know that he only plays against other people, either online match-ups or with his roommate in person. Would this prevent me from being able to create a character for him to use and access?

2. I want to create a Mii character that looks like him, and heard that you can create one from a photo? I found something called "Mii Maker" that says you can do this by taking a picture with the Wii U GamePad camera - however no one I know owns a Wii..... is there another way to make a Mii fighter character from a photo without using the Wii console?

3. I would like this to be a surprise - so if I am able to create a character - is it possible to create it in another console, or in another account, and then transfer it to him somehow, on his birthday? QR code? Send as a gift?

and FINALLY

4. There seem to be numerous varying opinions on which Mii fighter is best: Gunner, Swordfighter, or Brawler. My bf mains Bayonetta, and will sometimes use Dark Pit or Dr. Mario as alternatives - so which do you think would be the best choice for someone who uses these characters?