Gitlab pricing clarification please...

Not sure where else to ask this question, but I'm evaluating our team moving from github to take advantage of many of the features gitlab has to offer.

However it's unclear to me how the pricing works here, and I can't seem to get a clear picture on whether any one from my organization touching any portion our gitlab account has to be included in the group licensing bundle.
I'm considered the silver level option. We're a smaller outfit, 5 full time devs, so these would seem obvious to include in a group license package. However, we also would like to use the Issue Tracker services and allow "guests" (like the CEO of our company) to have access to certain views of the the issue system.

Would such "guests" also be required to be licensed too? And if we wanted to incorporate a scrum master to manage/track/monitor issues/features, would this person have to obtain a full priced license as well? Would seem a bit gratuitous since such users would be touching very limited areas of overall gitlab environment.