I've heard they did a lot of things that probably would have been the closest thing to communism in the 16th century (banishment of private property, no loans with interest etc). Did the founders of Communism get any influence from this at all?
No. There is nothing that indicates such an inspiration. Friedrich Engels did write a short book about Thomas Müntzer and the Anabaptist rebellion—which I am sure what inspired your question—called Der deutsche Bauernkrieg(The Peasant War in Germany), but in this book, Engels is very clear in downplaying any importance religion might have had, and rather, he focuses on the material conditions of society:
the political and religious theories were not the causes [of the conflict], but the result of that stage of development of agriculture, industry, land and waterways, commerce and finance, which then existed in Germany. This, the only materialistic conception of history, originates, not from myself but from Marx, and can be found in his works on the French Revolution of 1848–9...
So, while they, Marx and Engels, knew of the Anabaptist uprising, and the religious wars—as you expect them to, they were both highly educated Germans—they didn't have much praise for the religious aspects of the uprisings.
Marx himself was entirely irreligious, having been raised neither deeply Jewish nor Christian; his family had converted from the former to the latter to avoid discrimination, but they weren't practicing, so there isn't even a shade of religious inspiration in him. And Marx abandoned Christianity at a fairly young age, being clear about his own irreligiousity, if not outright atheism, before he enrolled at university.
The "true sources" of Marx's inspiration are rather to be found in Hegel, perhaps Spinoza, Ricardo, Smith, various Jacobins and other French radicals, Feuerbach's criticism of religion, and so on, than in some failed Anabaptist rebellion 3 centuries earlier.
See also my answer about Marx and religion here
Works:
Engels, Friedrich. The Peasant War in Germany. 1850
Liedman, Sven Eric. A World to Win. 2018. Verso
Marx, Karl. Early Writings. 1974. Penguin
Marx, Karl. Grundrisse. 1939