Yay, my second favourite topic ressurected.

Thanks!
Now i'd like to mention, my thoughts on the history of Silent Hill differ it seems quite greatly from your own.
Which of course is completely expected since the only 'true' canon History of Silent Hill is the Book of Lost Memories, which does detail much of the History of Silent Hill as given in the first three games and is an absolutely marvelous read if you have not read it yet. There is no translated print version, but the translated scanned pages can be found relatively easily on the web.
I enjoy that there are so many differing opinions however, so don't let my thoughts on that deter you. Your opinion is just as correct as mine, or anyone elses, since as long as you incorporate the facts, the rest is up to interpretation.
I think you're looking too deep into the whole Robbie the Rabbit thing. Although I do like the idea of your sort of 'curse' on the Rabbit suit fiction that you have going on.
In my opinion, the 'Robbies' simply appeared in SH3 because it's an amusement park, and they were simply mascots of the park that Alessa may have remembered from a trip to the park in her childhood. Their appearance however is a little incorrect in SH3, because it should be the same park as seen in SH1, but the Rabbits do not appear in SH1. In SH1 the park was a manifestation of Alessas nightmare, in most basic form, and of course we all know this. In the third game, since Heather IS Alessa and the park is a manifestation of Heathers nightmares, or correspondingly Alessas, there should be no Rabbits. The only possible conclusion that makes sense is that in SH3 the 'nightmare' world is actually a manifestation of both Alessa AND Heathers nightmares, fears etc, and heather visited a different Amusement Park in her youth, to which she manifested the mascots into the nightmare illusion of Silent Hills Lakeside Amusement Park. Therefore they might not even have anything to do with Silent Hill at all.
However, in argument to this, we are all aware that Eileen owns her very own Robbie the Rabbit doll (or costume?) which sits beside her bed in SH4. Why anyone would have such a creepy thing beside their bed is beyond me. We are supposed to assume that she bought/won the doll/costume in the Lakeside Amusement in Silent Hill. So.. where were they in the first game? Hrmmm. It's also logical to assume that the only reason Robbie appeared in SH4 was to connect the games a little more, and because 'Robbie' gained fan status and of course, a fan given name. Robbie.
Phew. I do go on when i start thinking about Silent Hill don't I.
I think I might know ONE thing about Saint Nicholas.
If my aging mind recalls correctly, and it might not so feel free to correct me, i believe a painting appears in SH1 in the Hospital, which names a man called Nicholas as the director of the hospital. 'Doctor of God' can only mean that Saint Nicholas was a man who assisted Alessa at some point while she was in the Hospital pregnant with the thing that The Order considered to be God. We do know that more people than Dahlia, Kaufmann, Lisa etc knew about Alessas imprisonment in the basement of the Hospital, because when Harry enters the room where Alessa was kept we see the Ghosly flashback in which Dahlia and Kaufmann are standing over Alessas bed discussing the power of God, and there are two other figures present. These may have been just members of the Order, or one of them may have been Doctor Nicholas.
Hope this stuff helps in some way.
I like the idea of writing something on Stanley Coleman BTW. A very underused character who gave significance to the plot of SH3 but was greatly underestimated in his importance.