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!
The conference deadline is likely for regular papers and is early to allow for review and possible revision. The workshop may be tightly associated or not, but likely has a separate organization (chair, committee,...). It also likely has a specialized purpose and participation may be less "controlled" than paper submissions so the deadline can some later.
Some workshops present "working papers" than may not actually need review and the workshop itself is a kind of review. Other workshops are actually working groups where people interested in a topic gather to do some work. Workshops may or may not publish anything after the event, and if they do it is usually less formal than for the conference itself.