k well here is my final point, i am going to address the glorfindel and who battled sauron isue then i am done.
glorfindel- here is a quote from return of the shadow page 214-215. "he came to the conclusion that glorfindel of gondolin, who fell to his death in combat with a balrog after the sack of the city and glorfindel of rivendale were one in the same: he was released from mandos and returned to middle earth in the second age." so since this is a letter from jrr tolkien i take it as fact that the two were the same. the only discussion left is wether or not the tolkien world an individual beleives in ends with the published works of the hobbit and the lord of the rings or if the individual beleives in the final form of the evolving world tolkien created.
k now for sauron-
return of the king appendix b page 455 year 3441-
"Sauron overthrown by elendil and gilgalad, who perish"
the complete guide to middle earth page 206
definition of gilgalad-
"in 3441 gilgalad and elendil overthrew sauron but were themselves slain"
definition of elendil-
"elendil was one of the leaders of the last alliance which overthrew sauron and, with his friend gilgalad, its greatest warrior. he was slain, along with gilgalad, by sauron on the slopes of oroduin, but they in turn overthrew their enemy"
definition od sauron-
"Sauron was overthrown by gilgalad and elendil, but killed both his foes."
and finally the most conclusive evidence is found in the simarillion, of the rings of power and the third age, page 365
"but at the last the seige was so strait that sauron himself came forth; and he wrestled with gilgalad and elendil, and they both were slain, and the sword of elendil broke under him as he fell. but sauron also was thrown down"
so there is my proof that elendil and gilgalad alone battled sauron. i never said that cirdan and elrond werent there. as a matter of fact elrond was gilgalads herald (complete guide to middle earth, page 147). as far as the circumstances involved in the fight (why didnt the others join in) i could speculate that the others were occupied with orcs or sauron was his own champion and men andelves sent there champions to battle him, but ush doesnt like me speculating.