Keeping in mind that I really consider Sir Melville to intelligent and decent (from what I know of him) to be the Ripper, if one really wanted a MM is the Ripper theory, it would be pegged on a diabolical hatred for Sir Charles Warren and those supporting him (the government of Lord Salisbury via Home Secretary Matthew) for refusing to countenance MM for that post in 1888. I can't really think of any situation anywhere where that kind of reaction ever set in. Appointed posts are matters that the people who have the power of selection can make or not make due to their own viewpoints (which can change on a moment's notice due to some wind change outsiders barely can see). A simple test really is, after 1889 (when MM has a post at Scotland Yard) did he ever show a real vindictive streak towards Warren, Matthew, or the Tory Party (that Salisbury, as PM, was head of)? I have never heard of it. He did not care for Anderson (and apparently vice versa) but did Anderson have anything to do with the 1888 rejection? I don't think so - where did he really know MM from?
Seriously about Druitt, MM does not seem to have known of him, Osrog, or Kosminsky until after 1889 had begun, when he begins to hear of activities regarding the investigation when he starts working at the Yard. Framing does not (really) be in the cards.