Such a postmodern viewpoint makes no sense to me. Since Dostoevsky intended to tell one, unified story, perceptive readers (whether Catholic, Protestant, Orthodox or Buddhist) will eventually see through his eyes. The rest is fantasy.
I found your Orthodox perspective fascinating and convincing, particularly as Dostoevsky and most Russians were Orthodox. I am less convinced that Dostoevsky is actively espousing Orthodoxy in the novel.
For instance, 'Lizaveta's kind of death IS a martyr’s death' while true within Orthodoxy, may not have relevance to the novel. Or does 'martyrdom' explain the strange lack of guilt Raskolnikov seems to feel for Lizaveta's murder? Similarly, where's the textual evidence for 'When person is too much deep in sin...God ends a person's life to stop its degradation'. Where is the evidence that God's 'acting was in directing all that in the best way for their salvation'? Scripture only says, ‘all things work together for good to them that love God’. Nevertheless, your Orthodox flavour alters little the story's interpretation, is quite intriguing, and provides insight into how many Russians may have understood the novel.
Sonia, like the three Marys at the foot of the cross, gives and gives and gives some more. You are right in saying that death has major consequences for the characters in both 'The Brother Karamazov' and here. While Raskolnikov's murders had a major impact on the lives of others, I am unconvinced the murders led to 'renewal and salvation'. They all have many years still to live, whether to salvation or damnation.
As Razumihin says, Douna and Raskolnikov coalesce in the way they think – like twins. Razumihin's name implies a pragmatic common-sense, which the more passionate 'twins' may lack. He is a moderating influence, the voice of reason.

