Yeah, those are Ming/Song style. One defining characteristic of Ming fonts is the triangular serif on the right end of a level horizontal stroke like 一. A FangSong and Kai will not display such a thing but will slightly taper on both ends and strive upward slightly. A Hei font will merely be a level horizontal line with no tapering or serif. A Yuan font is basically just a Hei with rounded ends and cutoffs.
Let me show you a very short exerpt from one of the most legible typefaces I found. I like using it at 9pt but I've set it at 10pt in this file. There are 2 weights that are usable at that size so I put them next to each other to compare. The heavier weight is closer to a bold, and I am not sure I'm fond of it, though it seems to handle complex glyphs remarkably well like 龜. I think you'll agree they are far cleaner and clearer than pretty much any Ming font on e-ink can be...and they (so far) seem very readable, not just legible.
Addendum: Here's an image that should help clarify the font nomenclature a bit:
