What alternative groups could be settled in Texas?
I have early read on this board about some German-Mexican colony society, which tried to make (Catholic) Germans emigrate to Texas (in the 1820ties), which more or less failed, could it have succed? Or could we see other European groups emigrate there? Would we still see a Texas revolution if it had been another group emigrating there?
Well, there was the
Adelsverein, the Society for the Protection of German Emigrants to Texas, founded in 1844 to encourage German immigrants to come to Texas. There was a substantial settlement of Germans in Texas, but not enough early on to make a substantial difference.
If you did get an German version of Stephen Austin, subsidized say by clever Mexican policymakers to avoid an overly Anglo population, then you might get a bigger amount of early settlers. Even then, however, there was usually a big difference between the early Anglo settlers of Texas and latter ones. Early ones were content to live under Mexican rule, so long as they thought that rule just and free. As the Mexican government underwent convulsions in the 1830s, the Anglos reacted (and one of the injustices they perceived was the unilateral emancipation of slaves by Anastasio Bustamante in 1829/30). However, the Texian Revolt in 1835-6 was one of a number of revolts from the central government when Santa Anna suspended the Constitution of 1824.
Having a greater number of a different national group may be interesting, though. There was a substantial number of Irish settlers in and around San Patricio, who's actions reflect a notion of being separate from the Tejanos and Anglos leading the revolt. It is important to note, though, that there were a good number of Tejenao (i.e. Mexican) supporters of the Texan Revolution (Juan Seguin was Vice President of Texas), but the Anglos outnumbered them in terms of overall population (30K to 5K IIRC).
And of course if Texas does revolt (which is essentially predicated on the actions of the Mexican central government) and if it does win its independence, then it probably still has the finanical trouble that it did OTL. It will need heavy foreign assisstance or to seek annexation by the US. US politics play an important role here and it's not implausible that if Texan society is seen as a mix of German, Irish, Anlgo, and Tejano influeces, that the Nativist groups in the US in the 1840s and '50s may combine with Free Soilers to oppose Annexation. If you avoid Annexation, then you also avoid the influx of Anglo settlers that came to Texas in the 1850s.