I am currently learning this Sonata. I noticed some differences in the the scores in the first page. I am using a newer edition from Henle, and in it bar three in the left hand starts a sixteenth note pattern. In a few other versions it's a tremolo.

Just curious what others here have done/would do with those notes.

Most likely what you are seeing is the same thing written different ways. The number of hashes between the flags in the tremolo indicates how fast it is supposed to be. So if it has two hashes, it should be sixteenth notes, three and it should be 32nds, and so on.