To answer this comment ...
Somehow these fundamentals do not attract the same emphasis in the Doctrine of Buddhism, where the focus is more on practicing the 37 x Aids to Enlightenment. I thought that the Buddha too, would have endorsed these fundamentals of Life and Living, whilst focusing on showing '"The Way'' to Enlightenment.
... as well as the original question, some people find that studying more than one religion (or more than one teacher) helps to increase their understanding of "everything" and sheds some new light what they learned previously.
On the other hand some people warn against it, e.g. that it might be a mistake to view Buddhism through the perspective of another religion.
It is true that the Gautama studied with several teachers before he was enlightened, and that many of the suttas are intended for Brahmins and so on.
I think there's quite a lot in Buddhist doctrine about "fundamentals" -- for example it is called a gradual training, it emphasises virtue as a basis, and generosity, and teaches about ideal versus harmful interpersonal relationships.
I don't know how Buddhism is taught, in your experience, I guess it's possible that the "emphasis" isn't on fundamentals.
I found this book interesting -- The Buddha's Teachings on Prosperity: At Home, At Work, In the World by Bhikkhu Basnagoda Rahula -- I think that shows that the Buddha's doctrine does include fundamentals for laypeople, even if you haven't heard them emphasised before.
I also think that different religions differ in their metaphysics -- for example, is there a God, or many Gods, is there eternal life, what happens after death, is there a soul, what are the divine or doctrinal commandments, how can we get supernatural assistance, what is the authoritative text and lineage? But that different religions might tend to say similar things about fundamentals, or see them in a similar way -- maybe respect for teachers and parents, something about social duty and maybe selflessness, and so on.
I read vedas in translation a long time ago -- wasn't taught them, didn't find them very interesting at the time, have forgotten them, so I can't quote them in this answer. But to pick a different example, i.e. Christianity, it's my opinion that the list of Christian "sins" ...
... is a pretty good match for some of the Buddhist doctrine. If that hadn't been a "emphasis" or "focus" when you learned Buddhism, then if you studied Christianity after that then you might have asked this question, i.e. "Is practice of Christianity a prelude to practice of Buddhism?"
I guess my answer is that it can be (and sometimes is) a prelude. But that it doesn't have to be, because Buddhist doctrine is large -- and it claims to be complete, i.e. teaching everything that needs to be known.
It's most likely true though that different teachers (and students) might somehow "emphasise" or focus on different parts of the doctrine. That's true in ordinary secular school too, when you're growing up the curriculum teaches different things in different years to different ages.