So ever since I read about amiibos I've been super interested in them, so I got three Yoshis to test them out. Each of them were trained differently and were never exposed to each other.
"Lunick" was the first Yoshi. I did just about anything you could think of with him. 1 v 1s. 4 players. All human opponents. All computer opponents. 2 v 2s. 1 v 3. Coins battles, ect. He seemed to grow the fastest, but he also developed a huge item dependency until later levels (about 40). He also began to develop different strategies depending on time/stock/coin battles. Time and coin he got pretty aggressive, while in stock he decided to hide away and just throw eggs a lot.
"Spazzo" was the second Yoshi I trained. I was a lot more strict with him. It was purely me versus him, no items, always final Omega stages. I started out playing as Yoshi, showing him combos and other things until he was being me. I then switched to Shulk and we started going evenly. He started figuring out what I do and I'd say before he hit 50, we were going 40/60 in favor of him. I think if we kept going he would destroy me. He seemed to develop a lot slower, but he learned combos a lot better and was pretty aggressive. Also to note I taunted after every kill and he taunted as well when he got kills.
"Joshy" was the last Yoshi that got... "trained". All I did with him was start a match and let him just wail on a non moving Mario. Items were set to low so he got to use them a bit. The most interesting part about him, was when I first started, he tried attacking for a little bit, until he just stopped. He wouldn't attack at all and I tried moving and he stayed about a forward smash distance away from Mario. Eventually he just immediately went from level 1 to 4 for no apparent reason and started fighting again. I didn't notice any quirks after that. (edit: It might be worth mentioning I was also able to push Joshy around on the stage. He didn't mind when I got closer, but if a started walking away, he would keep that roughly forward smash distance from me. I think he was just waiting for me to do a move and learn. Will experiment more on my reset.)
After they reached level 50, I put them in a couple of fights. I did 1 v 1s for each of them and a free for all. I did one for stock, time with items, and coin battles with items.
The stock matches went solely to Spazzo in the 1 v 1. He combo'd the others well and was able to do extremely well. Lunick won in the free for all because of his camping tactics, getting Spazzo and Joshy to kill each other.
In time, Spazzo lost the 1 v 1s. With items on, he had never seen them, and started experimenting. He didn't understand them and messed around with them. This lead him to be open to shots from Lunick and Joshy, who knew and used items before. Joshy beat Lunick and won the free for all surprisingly. I think the 1 v 1 was credit to him having a punching bag and learning his own combos. Lunick was more a jack of all trades and therefor wasn't as specialized as Joshy.
The coin battle was the most intriguing though. Since neither Spazzo or Joshy were exposed to coins, I don't think they understood what the coins were for. They actually avoided them while Lunick actively went for them. Lunick won pretty decisively.
Just as a final note, after each fight I exited the smash and didn't save amiibo data so they essentially never fought each other. And of course Spazzo taunted after every kill.
I would like to try this again and am open to any suggestions to improve or alter in some way what I did. I plan on getting new ones in the future, but for now I'm just going to continue to fiddle with the Yoshis