When you create a lead via a workflow, it’s currently not possible to determine which contact or company you want to associate, it will default to primary. (Might be due to the fact that association labels are not possible yet on leads?)
If you now create a lead via a contact workflow, this determines the contact that needs to be associated with the lead, but you cannot leave out a company association or determine which company is associated, it will default to the primary associated company to the contact.
This is a pity, as primary associations cannot be removed via workflows, and in the case of leads the primary company association can also NOT be removed manually on the lead.
You can add an additional company association to the lead via a workflow or manually, but if you then qualify the lead and create an opportunity, it again defaults to the primary company association on the deal as well, which requires a manual action to change the primary company on the deal.
Would be great if it will become possible to associate different records (based on association label between contact-company) to a lead via workflow and have the possibility to change the lead’s primary association manually (and preferably also via workflow).