I don't now enough about Texas so let's talk about the German perspective or the lack of thereof.
The "Prussian Navy" consisted before the 1848/49 revolution only of several small boats protecting their own coast. (European Powers still struggled with the debts from the Napoleonic Wars, and a fleet isn't a priority for Prussia as long as the coasts are safe)
A more obscure part of the 1848/49 revolution of Germany was the "German Navy" (still a really small fleet) build by the constitutional assembly to fight a war against Denmark. (And this fleet was some symbol and a source of pride for the nationalists, since being proud of a fleet (even if it is small) is one of the many aspects of 19. century nationalism).
None of the German States could project force to the American continent. They could maybe sympathize with such a scheme or maybe de jure protection but not more, and even such a thing could upset larger powers. And most of them are land-locked.
Austria has a coast to the Mediterranean, in the North, the Kingdom of Hannover, the Grand Duchy of Oldenburg, Holstein (in personal-union with Denmark), the Hanseatic cities of Bremen, Hamburg and Lübeck, aswell as the Kingdom of Prussia, and the Grand-Duchy of Mecklenburg-Schwerin have access to the sea. Mecklemburg is the most reactionary and backward part of Germany. The Hanseatic cities are probably interested in trade not in playing Grand Power. Denmark is already a colonial power and opposed to German Nationalism. Oldenburg is rather small. I don't know much about Hannover. A short search on the internet revealed, that the Kingdom of Hannover lacked any fleet, but proclaimed to protect the maritime interests of the German Federation in the North Sea (probably in the 1850ies when Prussia slowly became more interested in naval power).
(While the "Bundesakte" the "constitution" (or basic treaty) of the German Federation lacked any concepts how its Naval power should be organized (in comparison, there where rules how many troops each state should supply), there was a concept of the "Admiralsstaat" (admirality country) (
https://de.wikipedia.org/wiki/Admiralstaat ) a country which should supply and finance a potential navy of the German Federation. German Nationalists suggested that the Netherlands or Denmark could supply the German Federation with their Navy. Danish Nationalists rejected this. Nothing happened)
If German Nationalists have more interests in establishing weird German Republics on other places of the globe, German monarchs wouldn't support them. These nationalists are revolutionary radicals or liberals who oppose the old order. Bismarck managed to unify conservatives and old elites with the idea of a unified nationalist German nation later in the 19. century.
Even if the crazier German nationalists somehow manage to gain power in 1848/49 in Germany (which is really unlikely) it would be already to late, since Texas joined the US in 1846. I doubt that any foreign minister would support such a scheme which would bring nothing but could provoke other powers and costs lots of money.
I doubt that most settlers (even if they sympathize with German Nationalism) would want political rule by a German State (even a democratic unified 1848/49 Germany) on the other side of the Atlantic. It seems as if they have different problems and possibilities in their new home.
Another question would be, how the economic possibilities of Texas locked in the 1840ies and if there is anything in Texas which could interest colonial powers.