In general I like this article, it's an ok introduction to the expectations of an EM.
> The incoming list of prioritized projects will not be the same difficulty. That’s why it’s important to have a team of varied levels and differing skills.
I'd argue that's not why you want people of varying levels. Having juniors on the team is a) building for the future b) energizing and c) important for seniors to develop their skills as mentors. They should be working together with seniors, not taking the easy stuff.
> With this understanding, I can match the incoming projects with the appropriate individuals.
After a number of years as an EM, I tend to shy away from "matching" anything like this. I've a big believe in self selection with these things and try to avoid the role of task master at all costs. The only exception (I think) is when I need to take into account someone's development goals and actively encourage them to take on challenges that another team member would more naturally take. Example - if a team member really wants to learn iOS development, I'd actively encourage them to pair up with an experienced iOS dev on some tasks even though those are not things they'd normally be involved in.