Yes, re-downloaded content is a drawback of micro frontends.
Unfortunately, tree shaking doesn’t work for Moment.js at this point. But there are still ways to reduce Moment.js bundling sizes. A simple way is using
import moment from ‘moment/src/moment’.
Micro frontend approach has pros and cons. It provides decoupling by extra footprint. My other article, 10 Decision Points for a Micro-Frontend Approach, discussed this. You do have one more point, which is that it requires a server, or multiple servers.
You have asked a lot of interesting questions. It is part of the fun journey!
Thank you for your interest in my article.