can we use free desktop version for creation, and buy Enterprise for publishing,
Yes, you can use the free Qlik Sense Desktop for creating Qlik Sense apps.
are tokens needed for every person that watches reports, or just for creators,
Yes, you will need tokens for both creators and viewers. But you have a choice between assigning one token to one user or using a token for 10 login sessions. See the online help for more information: Managing license and tokens ‒ Qlik Sense. You'll have to decide what makes sense for your organization.
You don't need the Cloud version, unless you don't want the bother of having to provide and maintain the infrastructure needed to run Qlik Sense Enterprise.