I killed viola and apparently she was important for blood on the ice quest. Is there another way to complete on xbox? or is this a bad bug?

Either deal with it and keep playing or revert to an earlier save.

The UESP says that if she dies it is impossible to start or complete the quest but it might of been patched.

How ? I didn't experience this bug, but I can explain : you're told to speak to a dead person, it doesn't make sense...
It's even worse when you consider how little help she actually provides.

well its a bug because i would have failed the quest. I have to talk to her or it cant be finished.

I just realised who you meant but I think its impossible to finish the quest with her dead.

It is impossible to finish the quest "Blood on the Ice" with Viola dead.

The only fix is reverting to a earlier save.