The billy club look is due to incomplete pollination.

Yes, I think they are called "pickling" cucumbers but you can slice them too. But the ones with fat belly are not good for pickling. Smaller ones make better pickle.
The odd shape is usually due to the plant getting old and tired. Or the growing condition is not .

I never knew that, thank you both!

They may or may not be 'pickling' cukes. Possible? Sure, but there is no way to tell for sure as they are all deformed due to poor growing conditions. The ones in the picture all suffered from inconsistent soil moisture - mostly too dry - levels while developing.

Dave

Here is a link that might be useful: Pictures of normal pickling cucumbers