Awww that is too cute. I'm betting we will see more art of this once the SuperSon's movie and YJ starts up with them being kids. I have a feeling we're going to see more art of young him.
This! This so much! So many people think "Well if we do X to Character A then people will suddenly forget that they're mad about us doing Y to Character A because X is what they like right?" I've seen a lot of LGBT people complain about Jon suddenly being aged up AND rushed into a romance with a character we don't know enough about. This doesn't translate into readers. Unless these fans of this come out and buy his book and keep it high, maybe. But I think if Jay does turn out to be Magento to Jon's Charles, then you'll probably see some of these fans dip because they're not looking for a developed character they're just looking for cute and quirky art.
You can absolutely de-age him. There are a lot of ways to do it. Off the top of my head.
1. Speedforce de-aging due to some event.
2. Dimensional de-aging see Chris Kent
3. Sudden manipulation of higher powered reality warping character.
4. Pull a Reboot and have two Jon's running around like two Enzo's.
5. Pull a Ben Rilley and hey it' s a clone of Jon aged up. Real Jon is in a deep sleep right now.