well well, the only two of the founding brothers that could of been King/Emperor were Ben Franklin, and George Washington, in both cases the Succession is a problem, Washington having no kids of his own, Franklin's oldest child and only son was a Loyalist who when to England after the war and never came home. both the Adams were hated, Jefferson was a republican tomb stone with the voice of a 5 year old girl, Alexander Hamilton was too junior and seen as Washington's man
any way if we go with George Washington (George I or is it IV?) his heirs could be his step-grandson George Washington Parke Custis, or to the line of his brother Samuel Washington, this how ever is were things get messy, should it go to his little brothers oldest sons oldest son or to George's still living nephew? and given that Samuel Washington was married 5 times thats just throws every thing into the air, also George's youngest brother out lived him (by a little) so throw that in there
there was a plan to make Prince Henry of Prussia King of the USA, though he never had kids so a crown union between the USA and Prussia would be close at all times
if we make Ben Franklin king the crown would goes to his daughter Sarah Franklin Bache.