are there any experiences, with /or how to combine MobileFirst with Vaadin or GWT? The goal would be to combine the infrastructure/appstore/adapters etc. with Vaadin or GWT in a Desktop Application and or in a Android/Iphone app.
Google doesn't yield much here.
In general, the GWT model is not compatible with the Worklight/MobileFirst Platform model... which is why you are likely not finding any results about it. There might be some workarounds, but it depends on the particular issue.
As Stack Overflow is not about recommendations - feel free to first try, and if/when you have any programming-related questions, ask...