I think wedges are fab, too, and actually I think they make sense here. I like the outfit although I agree, I hope she will wear some beautiful, bright colours too.
Wedges are perfectly comfortable if you’re used to wearing heels, which Meghan is, plus everyone feels more at ease wearing the kinds of things one is accustomed to and comfortable wearing. She will also have to be conscious of not seemingly dressing down too much as that could be perceived as being patronising and/or dismissive.
I think the outfit works well for a daytime engagement that’s not too formal.