Regarding reality, there is a distinction in Buddhism known as the two-truth doctrine
that distinguishes between two types of truth, relative and absolute truth. So the dhamma contains these two types of truths. Relative truths are common-sense statements which are useful, but do not hold up considering ultimate reality, whereas absolute truths are statements that relate directly to ultimate reality. The dhamma makes few explicit classification statements about these two types, so it is not obvious which suttas express which type of truth. The two-truth idea is developed fully in Mahayana, especially by Nagarjuna, but the notion is also present in Theravada.
Theravada is ontologically agnostic, at least this is the official view. Some people have ascribed realism to Theravada, but I am not so sure about that. Perhaps you can find epistemological realism and moral realism, but I doubt that you find much ontological realism. It has always been my impression that Theravada leans heavily towards phenomenalism.