I studied The Bible for years academically and as far as I know there is nothing against any form of therapy herbalism etc., never mind what the various religious organisations may say, although again I am unaware of any negative views.
As above. But you will need an oil filter wrench of the fabric belt type. The filter is so close to the engine there is insufficient room for a chain etc to go round it. It is a straightforward little car to work on otherwise.
Old mechanic.