I’ve read the answer about the prohibition against entering a church. However, I’m wondering if the prohibition exists if the purpose for entering the building is not religious in nature. For example, does the prohibition exist if there’s a community meeting held in a church because it’s the largest or generally most convenient meeting place in the area? It is possible to get "permission" (perhaps from a Rabbi) to enter a church building for this kind of reason?

It is forbidden to enter a church even for purposes that are not religious in nature. The prohibition is an expression of Judaism’s total opposition to anything that preserves elements of idolatry (Maimonides, Commentary on the Mishna Avoda Zara I 4; Shach Yoreh Deah 149 1; Shu”t Tzutz Eliezer 14 91).