Washington was the CinC but at that time most of the Army was still made up of troops from the New England states so the leaders who had been in place still had considerable sway and rank. Men such as Knox, Greene, Sullivan, and Putnam were amongst that early cadre of leaders. If Washington couldnt get their support behind a plan, how enthusiastically would they then try to carry it out if simply ordered?

On the British side General Gage was the Commander of British forces in North America before the war and made the decision to concentrate all of his available troops in Boston to try to suppress the rebellion before it began, which in turn meant virtually the entire British field army became trapped in Boston. When Britain sent reinforcements they sent 3 Major Generals too, Clinton, Howe, and Burgoyne, who on arrival essentially formed a 4 man committee, with Howe and Clinton taking the field at Bunker Hill, and Howe taking overall command after the evacuation to Canada before later sailing for Long Island while his brother was the Admiral in charge of the supporting fleet. At the same time a smaller British Expedition under Clinton including Cornwallis ended up attempting to take Charleston failed, and rejoined Howe later in New York.

Source: PATRIOT BATTLES by Michael Stephenson