What I gather from the discussion here is that there is no way to have the 2nd degree murder charge dismissed on the grounds that the Affidavit of Probable Cause didn't cite enough credible evidence that the defendant didn't act under self defense and the same would hold had the charge been only manslaughter.
Look at grounds for dismissal as coming in more than one form. One form is that the allegations don't have evidence to support them, therefore the allegation itself is deficient. That would be a dismissal of the charge for want of certain inculpatory evidence. What's been discussed here is that the court cannot dismiss for want of inculpatory evidence of depraved mind. It can take the final act, and allege that this act, alone, is enough to establish depraved mind. The jury can reject that, but the judge cannot, as a matter of law.
Another form is to assert self defense. A judge is obliged, if asked, to conclude whether or not the preponderance of evidence supports a conclusion that the act was justified. The case can be dismissed on self defense grounds.
As for the contents of the charging instruments, if the charge is manslaughter, the state must negate the Chaper 776 justified use of force in the charging instruments, if the state charges manslaughter. This is because the manslaughter crime includes, as an element, that defendant did not act in self defense. But, in contrast, a murder charge need not negate self defense, because the murder crime does not include, as an element, that the defendant did not act in self defense. That difference makes logical sense, as "depraved mind" and "having sound reasonable basis" are mutually exclusive - at opposite ends of the spectrum of justification, actually.
Self defense can defeat either charge, murder or manslaughter, and can do so either by the judge or by the jury. If by the judge, the decision is based on the rationale in support of self defense. Logically, if defendant acted in self defense, he could not have acted with depraved mind, so in a sense the judge is finding absence of depraved mind. The only difference is the form and substance of the motion to dismiss.