Workshop versus conference deadline I noticed a particular conference had a deadline in January, whereas a workshop collocated at the conference had a deadline in May. Does this mean the workshop is merely using the location of the workshop, but is a distinct event? Example. I noticed the workshops proceedings are considered "non-archival meaning contributors are free to publish their work in archival journals or conferences" Is this the case with all workshops?
It happens from time to time. The idea is to give people who did not make it to the "normal" conference an opportunity to attend and present something. E.g. it could be work in progress without evaluation or projects at their very start. Usually, the deadline for workshops is after the final acceptance / rejection of the host conference.

Depending on the conference, there might be an extra fee for the workshop.

It depends on the workshop organizers (who are often selected by a "call for workshops") on how the contributions are published. 

This might differ between conferences!