Validate Assets
You can use IsDataValid to generated BP compilation message/warning/error as you need (for example, to tell your designers they missed something).
In 5.5 there is a new “fix me” overridable methods that will run code when you click on the text (similar to engine “fix” clickable text), more info here.
More info on zomg’s blog.
Validate project
You can use validators
See CommonValidators