All the revenue budget as opposed to capital budgets of Community schools ('normal' LEA ones to you and me), Voluntary Aided, Voluntary Controlled and Foundation schools are funded by the LEA via a formula which is mostly based on school numbers and other factors. The funding to LEAs mostly comes from funding from Central government - which in effect comes from you and me via taxes.
All schools then may get additional funding via grants, parental and other contributions and other income generation.
All Voluntary Aided and Foundation schools have their own admission policies - these may be different from the LEA policies.
As you would expect admission policies are heavily weighted towards a particular religion but also towards specialists like music etc and other religions etc - you don't have to be the set religion to get in IYKWIM.
All schools have to teach religion in some sort of context and cover all the main types - even "Church schools" have to teach about other religions. This is part of the National Curriculum - and is part of it because of the powerful lobbying of the church in effecting educational policies.
Faith schools are not just 'Christian' I believe there Jewish and Muslim state funded schools as well.
Surely, we should be arguing that religious teaching in schools should be an option - some want it and some don't - we live in a mostly secular society where the majority of people don't give a toss about religion - so why should all schools teach about it?