I was under the impression that the eastern religions all operate under the same axioms. I don't know any thing about Toaism except the Tao is apparantly the eastern equivilent of the logos, and so that brings in some syncretists and perrenialists into the mix. I thought buddhism and hinduism is essentially the same, except that the latter attempts to present an origin story and cosmology with all the bells and tassles that entails, whereas buddhism is simply stripped down to not care about any of that stuff and focus instead on achieving, through practicing ascetism (self denial), self-enlightenment and reach a state nirvana and see the ultimate truth that everything is interconnected and one and to destroy yourself to become fully become one with the universe. That's why people often say buddhism is less a religion, more a philosophy. Similarly, confucianism is a philosphical outlook, more than anything else. Alan Watts is a famous dude who was into buddhism and by extension hinduism, not from a Christian perspective mind. Look him up on youtube.
See first link for a book with what I believe presents semi Christian/syncretised/perrenialised perspective on Tao, and the second for a supposedly fully Christian perspective on Buddhism and Hinduism.
https://www.goodreads.com/book/show/265423.Christ_the_Eternal_Tao
https://www.amazon.com/Buddhism-Connexion-Brahmanism-Hinduism-Christianity/dp/1440050953
Needless to say it is my understaning that all the eastern approaches take pantheism as it's starting point, that is, everything is God. Which, as I saw R.C Sproul put it the other day in a vid, is really unhelpful as it means it's impossible to actually say anything meaningful about God in the first place, on the basis God is nothing in particular. It also means morality is relative and a matter of perspective, which is a horrendous conclusion that I don't know how people can live with. I believe the eastern traditions also view the material universe as a mirrage, to be overcome. Hence also the escaping the re-incarnation cycle and achieving nirvana. I think Hindu's specifically acknowledge that the universe is just a dream of God.
This is all skimmed from my passing readings online though, no in depth study. I may be wrong.
>they seem to not pose any active threat
I suppose the threat is that they are not the truth in full. Also with practices like yoga to release kundlini awakening etc. sounds like you'd be leaving yourself very vulnerable to demonic influences. I am also