Excellent news, was very impressed with him in Ireland last year. It will be intriguing to see how he fits into Koeman's plans as he certainly doesn't fit the powerful running style that seems to be the preferred player.
You know, this alone could be key for him. He can offer something different to the first team squad.
Not that this necessarily has any relation to what Koeman wants at Everton, but Walsh has a lot of similarities with that Clasie who Koeman absolutely loves. In terms of style/stature.