King Amalric I has only 1 surviving child: his son Baldwin IV (the Leper King). Princess Sybilla either is never born or dies early in childhood. The heiress to the kingdom is therefore Princess Isabella. Possible marriage prospects? (I doubt that she would have married Humphrey of Toron).
Why not Guy as Sybilla married OTL?
Keeping in mind that the reasons he's a bad choice aren't immediately obvious.
One of theMontferrat brothers (William, OTL first husband of Sybilla
or Conrad, OTL second husband of Isabella) is a more likely choice...
and if Isabella will ever marry Guy is almost sure who he never became king of Jerusalem (OTL first Baldwin and after his death the barons of Jerusalem tried to force Sybilla to seek the annulment of her marriage to Guy but she refused and crowned him king).
Why so? I'm not saying this isn't true, but why is it going to be true here?
And its not as if all the barons of Jerusalem minded Guy, they were too divided for that.
All the most important barons do not want him as King. They gave the Crown to Sybilla only if she divorced to Guy (she was madly in love with her husband and tricked the Barons). The Barons don't like Guy and don't think him able to being a good King and leader for Jerusalem (and they was right).
http://www.historyofwar.org/articles/battles_hattin.html "faction" kind of implies supporters.
Trying to find more specifics. I think Reynald accepted Guy in the sense of not opposing him becoming king.
Reynald of Châtillon was not one of the most important Barons, practically all his power was from the land of his wife and her son...
He was, exactly as Guy, a lord from Europe, who became powerful because he marries very well (first he become the second husband of the ruling Princess of Antioch, then marry the widow of a very important baron with a young son) and he had many of the same flaws of Guy and was not much liked by the barons for this reason. He was practically the natural ally of Guy (and the other of their faction mostly was born in Europe and not in Outremer).
So, the Lord of Transjordan isn't an important baron because . . .?
And the others of that faction being from Europe and not Outremer isn't the same as them being insignificant.
Because he was not the Lord of Transjordan, at least not in his right (his rule was in name of his second wife, who was the heiress of the lands).
And I know who the European faction was neither insignificant o powerless but they was not barons of the reign in their own right (who was all born in Outremer) who was the men who had given the crown to Sibylla on condition that she divorced from Guy (because they do not want Guy as King). And I think who Reynald of Châtillon (who had many of the same flaws of Guy, and was married first to heiress to Antioch then to heiress of Transjordan) and his rule on his wives lands was one of the reasons why the barons did not want Guy as King.