Blanchard may have overestimated the role of autogynephilia as a cause of desire to transition to the opposite sex, but I don't think anyone could question the reality of the phenomenon, or reasonably deny that it plays a role in some transgenderism.
(Snipped post down to last paragraph as I'm not responding point by point.)
I think I mostly agree. Autogynophilia exists.
I also think that autoandrophilia exists. Though Blanchard instead calls it "autohomoeroticism" which he defines as "a female's love of (the idea of) herself as a *gay* man." (https://twitter.com/BlanchardPhD/status/986233413588877313)I'm not sure how he defines a condition where a female loves the thought of herself as a straight man. One respondant posted an article that suggests that some women do fantasize about being a male without the homoerotic element Blanchard posits. (https://surveyanon.wordpress.com/2018/03/24/autoandrophilia-survey-results/) I think there are a few gaping holes that Blanchard doesn't address.
I also agree that these auto____philias can potentially lead someone to actually transition to the opposite sex. But I question the proportions. First, because subsequent work suggests that there are those who don't fit Blanchard's categories, and second because I find it difficult to determine the direction of causation in each individual case.
In any event, you are correct that the criticisms of Blanchard have been used as a means of dismissing Autogynophilia entirely, which is incorrect, and not what the critics themselves seem to do. But it's also true that Blanchard's theories have been used by the other side as a club to say "See! They're just delusional perverts!" Which is equally incorrect. (And, I think, a mischaracterisation of Blanchard.)