Mechelin was such a freak occurrence that it would almost certainly be butterflied; if nothing else, the need to coordinate with their Dutch allies and the resultant changes in deployments mean that the air travel will be different.
Likewise, the presence of Dutch forces as an active, advancing enemy means the Allies and Axis will both take somewhat different approaches. An Axis Netherlands means that the defense of Belgium has to deal with a threat along a different axis, and that will change how the French planners respond (and since an Axis Netherlands implies different a different pre-war diplomatic/political situation, planning also looks different; for one thing, a revanchist Netherlands as well as Germany might mean the Belgians are less reluctant to do joint planning, and certainly means the Belgian-Dutch border is better fortified). That alone would change planning on both sides (especially if the Germans see a political/diplomatic need to support their Dutch allies more heavily than the OTL move into the Netherlands, or conversely avoid sending forces there at all).
We also strongly disagree on the political effect of a less successful Dunkerque, but that's a topic for a different thread.