High Quality pets should be on top aka Descending order.What is Descending order: it's when Pets are arranged from Mystic(High) Quality to Common(Trash) Quality.
Scrolling every time to get what you want(maxed pets) is not cool at all.
Do you want to know why this will never be fixed? Because this is not a coding/design mistake, it is a way to make you spend ALL currency on upgrades; a kind of stealth reminder.You can still avoid scrolling, just pick up to 35 of your fav companions, and F it.