Can you cite a workshop or conference in a paper?

The issue here is that conversations are not normally "on the record." The point of a citation is verification: you are giving credit by citing the "original source" that you are using. Since you would not really be pointing them to material actually associated with the workshop, you should cite "Private Communication" with the involved individuals—although you could cite the event as the "location and date" fields for the communication.

Typically, only published sources should be referenced. Exceptions may be personal communication and reports. Quoting, for example, a discussion during a meeting is therefore quite difficult unless you can quote the persons (and that meeting) as personal communication. The problem is that the discussion or statement(s) are not officially recorded somewhere. There is of course nothing wrong with simply printing out the occurence of the discussion at the meeting in full text. I am not sure if I have seen it but something along the lines your first example with names (and titles) clearly indicated. Just remember to clear the statement with the persons you quote and do not forget to state the date of the conversation/conference.

You could mention the people with whom you discussed in the acknowledgements "thanks X and Y for helpful/... discussions" and cite the conference in the text.

To cite it in the correct style, I would recomment that you contact the editorial office and ask. I once asked about the style of referencing a thesis and recieved an answer very fast, so this is the safest way in my opinion.