SharePoint List - Roll up from multiple lists

I'm a bit late now John Condron 
You can create an add-in which recursively iterates over your 3 Teams sites and collects all items of all lists in these subsites which use the particular content type you want to roll up. If all lists have the same name you can simply select the lists by name. The collected list items can be written in a separate list.
You may want to try https://appsource.microsoft.com/en-us/product/office/WA104380549