The 'Grand Duke Michael question' is intriguing, and unlike Nicholas Michael was a potential focus for trust by the moderates in the Duma as an unknown quantity who had no 'hard-line' conservative record or was disliked as a reputed playboy or spendthrift. He had been living quietly and modestly and keeping out of politics since his return to Russia to help with the war effort in 1914 - though until then he had been in disgrace with Nicholas and the court 'hard-liners' for letting the Imperial Family down by marrying (1912) a divorced middle-class woman, Nathalie Wulfert, who had children by a previous marriage and a bastard son by Michael, George, born before their marriage. They had had to go abroad to marry as the Czar had refused to allow the marriage as illegal under Orthodox Church law (which did not recognise divorce), and until 1914 had mostly been living in the UK - as of July 1914 Michael had leased the country house in Sussex which is now Worth Abbey school. Michael, ten years younger than Nicholas and until his marriage an easy-going and unpolitical Guards officer, was dismissed by his siblings and at court until then as an unpolitical 'lightweight' of no importance, and apart from his standing up to his brother over the marriage was not known for any strength of character or political interests/skill. This made him a 'blank slate' on which people could pin their hopes though the Church and conservatives disliked him, so he could have been a crucial 'figurehead' for a new regime in February 1917 had he been a stronger character or interested in 'doing his duty' to save the dynasty. In the event, by the time N finally abdicated and ruled out his son Alexei as heir, the majority of the Duma and the crowds in St Petersburg were expecting the end of the dynasty, the troops could not be relied on to rally to the Crown, and Michael changed his mind after an initial acceptance and declined the throne. He appears to have taken soundings among the senior Duma moderates and decided to accept their advice that political stability and his personal safety could not be guaranteed and announcing him as Czar could spark off more riots and cause stronger popular rallying to the Social Revolutionaries and other militant republicans (probably prompted by the self-assembled new Soviet ie workers' / soldiers' council at the Tauride Palace in St Petersburg, which could call on regimental agitators for help). This could sweep the new Provisional Govt away; without any Czar the PG stood a better chance as it could win popular goodwill as a 'new start' and republican.
Possibly a stronger, more determined, and better-known Michael would have stood a better chance or he could have risked the wrath of the Soviet and the troops/ workers; as it was he did not even try. The unknown is whether the politicians who advised him were too scared of another outbreak and the fall of the precarious new regime created by the Duma to rally to him, and if this would have been so if he had tried to make a stand. Possibly his late older brother Grand Duke George (d 1898), a cleverer and more sensitive figure who had died of TB as a young man and was trusted more by Nicholas (closer to him in age), would have stood a better chance had he been alive and of good reputation. There were some liberal Grand Dukes like Nicholas' cousin (and his sister's husband) Alexander Michaelovitch , who had been advising N strongly to get rid of his wife and her advisers and proclaim a new democratic govt in Jan-Feb 1917 but been ignored, to back him up - and the British ambassador Buchanan who had backed Alexander and advised N similarly but been snubbed. (The British aim was to avoid chaos that would push Russia out of the war and help Germany; it has been suggested recently that the M16 agents in St P tried to help this cause by involvement with or even suggesting the killing of the hated Rasputin in Dec 1916.)
The state of the St P garrison in Feb 1917 was crucial as they could have rallied to Michael and put down a rising before it went too far, or at least rallied to a new govt that declared for a govt responsible to the elected Duma plus a constitution and forthcoming elections. Most of the most loyal and respected middle-ranking officers and the usual pre-1914 regimental and garrison junior ranks had been sent off to the Front in 1914-16 and many of them had been killed, with brave but naive upper-class officers 'leading from the front' (as with the British officer elite) and getting mown down by German machine-guns - especially at the Prussian battles of Tannenburg/ Masurian Lakes in aut 1914 and in the 'Great Retreat' across Poland of
1915. The Feb 1917 garrison in St P was a mixture of hastily-promoted junior, outsider officers who did not know their men and rural peasant conscripts; this disintegrated or revolted easier than the old, 1914 garrison would have. Had more of the 1914 Guards and garrison troops been in place , I can see them rallying to a respected liberal new Czar - though this would have been easier had the Czar decided to abdicate or appoint a leading liberal as Prime Minister with extraordinary powers a few days earlier, when the situation had not gone so far for a republican outcome or the Soviet not assembled. As it was, N was out of touch at army HQ (Stavka) and then shunting around the rail lines trying to get back to Tsarskoe Selo and unable to be reached. If the military mutiny is smaller and suppressed, the street riots could be defeated by a united army - with the Palace Square or the square in front of the Tauride Palace (Duma HQ) as the equivalent of Tienanmen Square 1989?
Given the attempts to persuade N to declare a 'responsible' govt led by the Duma and plan other confidence-building measures ahead of the Revolution, it seems that assorted Grand Dukes (led by Alexander), ambassador Buchanan, and others were trying to push N into doing something that would abort a rising but he refused to act - as usual. (Had he not been acting as army commander at HQ, he would have been easier to reach at Tsarskoe Selo.) The outspoken mother of his next heir after Michael, his first cousin Grand Duke Cyril, Marie Pavlovna (by birth German), even spoke vaguely of organising a coup with the Guards (Cyril commanded a regiment and hurried to declare allegiance to the Provisional Govt in the OTL Revolution) to push the unwilling Nicholas out of the way and pack his ultra-conservative, obstructive wife Alexandra into a convent. This was prevented by the actual outbreak of revolt and there had been talk of a military coup before, but it is a leading 'What If' of 1917 - and had the regimental elite been in better shape and their troops been long-serving and loyal ones it might have worked. Or if the destructive influence of Alexandra had been removed - say, by a nervous breakdown after Rasputin was murdered - Nicholas, who was once referred to as like a cushion as he followed the advice of the last person to sit on him, could have listened to his relatives and formed a new govt. This might then have failed to solve problems or defeat Germany in 1917 and annoyed soldiers mutinied later - but it would have given Russia a breathing-space or made the moderates stronger.
Even if military disaster impels Russia to a humiliating truce and disorder later, any elections or popular uprising in late 1917 or 1918 could benefit the SRs not the much smaller Bolsheviks and if Lenin has not been let back into Russia by Germany he would be unable to profit from a rising. That way, a Bolshevik rising is 'too little too late' like the Luxembourg group's rising in Germany, it goes the way of the July Days in OTL, and it would be a case of the SRs vs the Army and scared moderates (a bit like Germany 1919?).
