Deploying new team sites and Teams - what is the best thing to do?

Hi Aragorn. 

I would personally go with Option 4 for your rollout which is to create your department sites as Modern Team Sites i.e. you create them from the SharePoint home page. Then, later on, when your rollout plan allows, you can create a Team from those sites. The only thing to consider with this, is that any documents which are created on the site won't appear in Teams straight away unless you've created the relevant folder structure in the documents library already. E.g. if I create a "General" folder in my document library, this will map to the General tab when I create my Team.

This way, you will only have one SharePoint site associated with the department which your users can populate with content, and then when the time is right you're adding functionality rather than giving them something else and expecting your users to roll with it.

I hope that helps