[soyclocky]

So essentially one can follow the Truth's/Path and be a Buddhist without even having specific beliefs about reincarnation/rebirth? Is animal-human rebirth a mandatory belief to be a Theravada Buddhist?

Buddhism is a practice and a way of life, not a dogma - there are no beliefs in Buddhism - the practice and the way of life dissolves belief. There's nothing mandatory in Buddhism. We're on our own with the practices, and we test the teachings with our experience of them.