I could only vote for number 1 in the poll, as it is the only one that is indisputable. However, as others have pointed out, it's probably a mixture of 1, 2 and 4.
As for the Eru=God idea, it's not something I've ever thought about much, but my take on it is that Eru is less like the benevolent Christian God that we all know and love (!), but slightly more like the chaotic Gods of Greek and Roman legend - specifically Zeus/Jupiter. So, while I know it's probably a bit lazy (and possibly sacrilegious by Mr Marley's exacting standards

), but Eru=God (but not
our God) works for me as a general rule.