Though in 1866 the most prominent Dutch newspapers were unanimously judgemental of Prussia's expansionism, only the Arnhemsche Courant stated any concern over a Prussian attack on the Netherlands. Interestingly enough, comparisons of German and Dutch culture were not really made, and the Prussian threat was primarily viewed as a military one.
Then what about after the end of the Franco-Prussian war? The Netherlands having pursued an isolationist policy since the 1830s, both France and Germany were condemned for their aggression and the war was used to show that 'one cannot trust on the sense of justice, honesty and generosity of their powerful neighbors'. (Author unknown, 'Arnhem, 1 Augustus.' Arnhemsche Courant, 02-08-1870.) Throughout articles from this period that discuss German nationalism, the suggestion that the Dutch nation and the German nation could actually be united don't seem to be discussed at all.
In fact, a brochure called Nederlandsche Spectator attacked the German economist Adolf Wagner for suggesting that the Dutch, Swiss, Flemish and Scandinavian nations are in fact part of the German nation. This idea is treated as reprehensible, and is suggested to be nothing more than a subtle attempt by Germany to expand even more within Europe. Louis Philippona, a journalist working for the Algemeen Handelsblad also opposed any suggestion that the Dutch were related to the German nation:
Boven Duitschland, boven Frankrijk, boven alle landen der wereld heb ik mijn Nederland lief! Trots al wat Duitschland en Frankrijk edels, groots en voortreffelijks ontegenzeggelijk in zich bevatten, vond ik er noch die ware, gematigde en rationeele burgerlijke en politieke vrijheid, noch die practische verdraagzaamheid, noch die rust en dien vrede, waarin ik mij als Nederlander verheug, endie mij steeds doen denken: vrij en gelukkig zooals in Nederland! (More than Germany, more than France, more than any other country in the world do I love my netherlands! Despite all that is noble, great and excellent that Germany and France possess, I cannot find the true, moderate and rational civil and political liberty, nor the practical tolerance, nor the tranquility and the peace, which I as a Dutchman enjoy, and which always makes me think: free and happy as [I am] in the Netherlands!) (Louis Philippona, *'*Rotterdam, 2 Maart.' Algemeen Handelsblad, 03-03-1871.)
Through rhetorical devices such as these articles, citizens of the Kingdom of the Netherlands became even more aware of their Dutchness that was completely separate from any possible relation the Dutch culture might have had to Germany. This bigger national consciousness was partially the result of hostile Dutch intellectuals, who painted the new German Empire as an aggressive state that was seeking to absorb smaller, and weaker states such as Belgium and the Netherlands.
I think that the importance of these articles' role in creating a Dutch national identity is relatively low though. Within the discourse on Germany from this time, most of the discussion was about how the Dutch could military and diplomatically counter a potential German military threat, and not about whether the Netherlands were or weren't part of a pan-Germanic nation. This was because to a large majority of the Dutch people, the Netherlands had already been a completely separate entity from Germany since the founding of the Dutch Republic. The process of disseminating a national consciousness had moreover already started in 1815, when a national historical curriculum started to be taught in public schools, and had been strengthened even more when the Netherlands turned isolationist after it had been betrayed (in the eyes of the Dutch) by the Prussians, French and British when these countries supported Belgian independence.
For further reading, I'd recommend: Ottenheim, N. Distant Neighbors. The Role of the German Unification between 1864 and 1871 in Dutch Nineteenth-century Nation-building, 2019.