Given your constraints, I'd say that Elm is an excellent choice. It's simplistic enough to be approachable, the easy web integration is a feature (not a drawba

Given your constraints, I'd say that Elm is an excellent choice. It's simplistic enough to be approachable, the easy web integration is a feature (not a drawback as you mentioned), and people are doing "real work" in Elm so they will be able to use it for years moving forward.