Imperfect as our homeschool was (ailing parents to care for while trying to teach, everything falling on me as the only teacher, and my limited prowess in science as well as having to relearn many math concepts after almost fifty years), one place we never went, was whether any religious truth could be found outside of orthodox, traditional Catholicism to the exclusion of the latter.
In our world geography class, I took a brief amount of time to explain the major features of Islam, as well as what's wrong with it, ditto all other major world religions, but that was it. One Lord, one Faith, one Baptism.