I couldn't possibly go into all the points raised but a couple of things came up that stuck in my mind that I wanted to write some more thoughts down about, before they slip forever from my mind - so this post is really just for me to note down my meandering ideas!
The first thing I've been thinking over was a point made by one group member who asked about the definition of 'supernatural' in relation to science, saying that if it's really about things that cannot be observed or tested scientifically, then would things such as the interior of a black hole or the universe beyond the horizon that we are currently able to observe be classed as supernatural? It was a difficult point to answer at the time, and I'm not sure anyone actually did satisfactorily. Having thought about it a bit more, this point occurred to me. Supernatural things that are claimed to exist by religions, superstitions, some pseudo-science etc. are said to be separate from our familiar material universe and beyond the ability of science to investigate. However, they are also claimed to interact with our material universe in all sorts of ways, so there's a contradiction there. While it appears that scientific concepts such as regions of the universe that are forever beyond our observable horizon can never be proven to exist by observation (obviously) - no claims are made that they interact with our part of the universe in any way. Those sorts of claims are made for 'supernatural' things like a realm where souls go after death, God coming to Earth and doing all sorts of crazy stuff, etc. They are 'supernatural' because the evidence for those claims is very weak and there simply is no mechanism for a non-material realm to interact with our material one - in either direction (i.e. the dead talking to mediums, of souls leaving the body to another realm in the first place). It's not really an answer but it's a distinction between what is commonly thought of as 'supernatural' and the observationally unprovable things that science predicts, I think.
Secondly was a discussion I had with Chris Eddy, one of the philosophy society members here (which came up briefly in the meeting again). That particular exchange is a bit on the confusing side for me, but it has lead me to carry the thought process on a bit and come up with a short and simple argument of my own. Chris's argument starts with the claim that religion sets out to class some actions as absolute or unconditional - for an obvious example let's take one of the ten commandments, "Thou shalt not kill". We're talking morality, so far so good. But it seems pretty obvious also that such rules don't apply to the God of the Bible (and most other religions I would imagine, I'm just using Christianity as I'm more familiar with it), as he kills vast numbers, kills on a whim and demands others kill for him. So clearly those rules are neither absolute nor unconditional, because they don't apply to you if you're God - that's a condition! If we then consider the famous question about God and morality posed by Euthyphro:
"Is what is morally good commanded by God because it is morally good, or is it morally good because it is commanded by God?"
The answer clearly has to be the latter, given that God is supposed to be morally perfect (and the source of all morality in the first place) - because if the moral rules were external to God, he would follow them. As he doesn't, those moral rules must be moral because they are 'commanded' by him. But then that leaves you with the situation that these moral laws are no longer absolute or unconditional, because God frequently changes him mind! One minute he's saying "Thou shalt not kill", the next he's commanding the extermination of entire races (or simply wiping them out himself). So the idea that because our moral laws come from God means that they are objective also fails. Moral laws cannot be absolute, unconditional or objective.
Some Christian theologians (I'm thinking in particular here of Douglas Wilson and William Lane Craig) do state that it is what is commanded by God that is morally good. Yet they don't seem to have a problem with him ignoring his own rules, and how that (it seems to me) shows they are not really what they think they are.