I recently saw a rpely to a question stating that a Jew is not permitted to enter a Christian place of worship because the Rambam stated that Christianity is considered idolatry(which is quite obvious since they have images of dead men, crucifixes,etc). But also, I read one response that says that Islam is not considered idolatry, simply that a Qur’an is considered a collection of falsehood and lies. Now, my question is, can a Jew enter a mosque for any reason whatsoever, since allah is not the G-D of Israel, but in fact the name came from a Meccan moon god(they still claim he is our G-D, though)? What about a Baha’i or Sikh house of worship,since they,as well as Muslims,are forbidden to make images?

Entering a Moslem mosque is subject to dispute. The Tzitz Eliezer (14, 91) prohibits like any other idol worshiping place and most other opinions allow (Yabia Omer 7 YD 12) For the other religions, I don't know what they believe in or how their temples operate but I assume they are also a form of idol worshiping and as such, entry to their temples is strictly prohibited.