The English Civil war was a damned close affair. By rights, the king *should* have won, Charles really was his own second-worst enemy.
Carthage had only a limited chance at success given the Roman alliance system it was up against. The Romans could just commit greater resources. Though the first one could have worked out well for the Punic side, it was a miracle Hannibal lasted as long as he did.
The ARW - muchly like the Civil war, except that the British government was, if anything, more inept and less emotional. But once war started, I don't think their chances at winning were *that* good in the long run, their victory would have been containing the confrontation and defusing wider issues.
Central Powers victory - depends on your definition of 'victory'. Going out with salvaged pride and avoiding surrender would have been a possibility well into 1917, (and 1918, had it not been for the US). But a full victory, as in 'all strategic goals reached', was unlikely in so evenly matched a slugfest.
I don't see any of the others as very likely, though I guess the CSA *could* have played on northern war-weariness...