Batman could take a no name fodder Wendigo. Feral was able to take one out like it was nothing. Batman has gadgets, and far superior intelligence.
It would depend on the villain from his rogue gallery. Any character standing in front of one that manages to get bitten is done for I guess. I can see Killer Croc running around screaming WENDIGOOO for example.
The curse being transferred by a bit or scratch was due to Tanaraq and not normal.
There is some pretty low level wendigo as mentioned which batman and the villians could take. Average incarnations or upper levels they wouldn't have a chance sans prep. Clayface would be a stalemate as most wendigo don't have smarts to permanently take him out.
No one knows but even when they went to vegas they said they weren't normal wendigo. Other then hulk and recently in amazing that has never happened before.
Also in amazing xmen when the wendigo crossed the border they reverted back to a human, but in hulk they had no issue.
Like -KM- mentioned. The upper class Wendigo's were extremely beastly. One took on Alpha Flight, and the X-Men combined. Batman is good, but he isn't invincible. I'm not sure why people act like he's sun dipped Superman?
its because he's skilled, so much so that he's put on the level of low metas, in other words his fighting skill is so great that he's able to hit harder than Deathstroke ( by his own admission ) and fight better than guys that can level buildings. Even in reality, skill can make up for a smaller or weaker person getting into a fight so its not that far fetched really.