Hi, I'm the current author of Vintage 101 on MTGGoldfish!
Uhhh, Donate wouldn't do much there. You'd just be giving them a creature. You can call a judge if you like, they'll just stare at you.
Companion is something you declare at the beginning of a game, sort of like Commander. Once the card is cast and in play, it's treated like any other creature.
@grizzly I mean, I am always trying to show off those decks that are interesting as I come across them and whatever happens that week. The Challenge results do however, tend to be focused on what is doing well since the goal there is to help people understand where the metagame is at.