Hi @BrianS,
You are on the right track in all your steps and assumptions. Great to see you have soaked up the knowledge we try to share through training videos! 
Using Aggregate(…) in the ‘list of value’ dimensions and then using these members in a tuple with the measure is the suggested and fastest way to do this with MDX.
You are correct that you could use a Filter and Sum a measure over a filtered set of issues, but that calculation should be reserved for more complex filtering requirements (with OR statements, for example). In this case, the tuple would work faster.
There was an excellent presentation about Translating JQL Queries to eazyBI Reports by Janis Plume in one of the eazyBI community days. If you like, you can go over the slides here: eazyBI Community Days, Day-2 Training Presentations.
Lauma / support@eazybi.com