Here's how I would do it: There's five mechanics every map would have

You must turn on the electricity to access certain doors. The mystery box Every 5~6 rounds is a dog round There's the four core perk colas plus one that's unique to the map Pack'a'Punch is somewhere

After those five things, every map can include one, maybe two, extra mechanics. This could be linking teleporters, monkeys instead of dogs, the moon landers, low gravity, maybe some collectible you need to unlock pack'a'punch.... No more than one of these in a map, maybe two after a certain amount of testing.

That way, the casual game mode doesn't require hours of studying youtube videos on how the pros solve easter eggs just to play them. Of course, the specific map layout design should focus on giving players multiple strategic options to choose from, but this comes after the core five plus one mechanics are in the game.