About the Dutch situation:
Assuming that there will be enough unrest in Spain that is not able to focus on the Netherlands, and reading the rest of the thread it seems there is good reason to suspect that will happen, I think this will happen.
First the Dutch will appeal to the new government to listen to their demands, religious freedom for protestants, lower taxes, more autonomy, etc. Assuming that whatever new government there is refuses this, a very good chance, the Dutch will continue their rebellion. I think pretty soon all the areas that had signed the union of Utrecht (basicly the Dutch speaking parts, including most of Flanders and Brabant) will be cleared from Spanish soldiers, who will be driven to the catholic and loyal south (Artois, Hainaut, Namur, French speaking Flanders). Spain is busy and unable to sent reinforces and the Dutch Spanish war continues here. Antwerp will be used as the Dutch capital. Zeeland, Flanders, Brabant and Holland will become the most important provinces, where the rich traders will be and from where colonisation will start. Because the Netherlands is still at war with Spain, but not with Portugal, it will focus on the Spanish colonies. So I think there is a chance for a Dutch Philipines and various Spanish Caribean Islands (but no Dutch Mexico or Peru, I don't think the Dutch are able to do that). The Dutch will still be interested in Indonesia and India, so trading posts will arise there, but without a Portugese-Dutch war, the Portugese colonies are safe.
A Dutch colony near New York and at the Cape are still likely to happen.
The end result might be a wealthy Dutch state including Flanders, Brabant and possibly (parts of) Limburg, Namur and Hainaut with various colonies. At the end of the troubles in Spain they will probably want to become independent and are in a lot stronger position than OTL.
Another interesting thing that could happen is that The Netherlands ask a foreign power to rule them. They did that OTL, but both France as England wheren't interested, because they feared Spain. With a weakened Spain one of them might agree to help the Dutch. So this might not lead to an independent Netherlands, but to a French or English Netherlands.