I think that these are all good points. My own 2-pence worth is that the 'something' is, by definition a supernatural entity.
The issue is that when string theory was posited I do not believe that this would satiate such a persons belief in 'something'. They would not say "ahh, yes I knew I believed in 'something' and that 'something' happens to be 11D supergravity".
I think that no physical law or process would ever fill the 'something' because this 'something' is always an unreachable supernatural process or thing.
Or possibly McCulloch may have hit the nail squarely on the head with
McCulloch wrote:"I've got my own religion and I don't want to argue with you about the particulars. Go bug my neighbour!"