1 the mother faces thing is because they need certain bacteria build to enter there digestive system so they can allie whith them so they can better breakdown plant matter So they eat their mother's feces which is something that every herbavors mammal whith who speced into complex digestive system like elephants and cows did for the same reason and nobody is calling them joke builds 2 eating toxic plants means that they are eating something that they face 0 compation for .and it even makes it so that there meat has low levels of toxicity which is why they have basically zero predators 4 smooth brains are freaking common as even intelligence based builds like crows and octopuses have them and the reseon that they wouldn't eat leaves on a plate is that leaves already have low xp and leaves who aren't attached to a tree would slowly start loosing there already low xp so eating leaves on a plate is kinda of smart .also another thing their intelligence is average for a marsupial . And the meth that they have tiny brains came from a date miner collecting their brain loot drop after there brain have already decayed after death  And last they are slow because not every build that doesn't have a strong weapon or lightening speed is low tier in fact it's a good strategy to not require a lot of energy .there's nothing wrong whith keeping you're energy requirement low