You are not a dumb foreigner.
Please don't deprecate yourself and other foreigners.
Welcome! I see others have answered most of your questions.
Most schools teach religion, which is generally Christian biased, although there is teaching about other religions it tends to be less..
You need to visit schools and ask the question. You will not be able to tell by the name of the school, the prospectus or the funding mechanism.
I didn't want a Christian emphasis in school. But when we visited schools, the head of the community school, with, on paper, no religious affiliations, went on about their links with church at great length. This school had stressed teachers reciting lists of targets at me, and chaotic classrooms.The head of the RC school was clear about the religious activities, but also made it clear that their main priority was happy, relaxed children and families. The children were calm and welcoming.
You can guess which school I sent my kids to, can't you.