About the mirroring I've heard that just mirroring the sprite is a hack and not good practice but I'm a beginner right now and trying different stuff.
less of the first, more of the latter!
Hearsay of good/bad practice is a double edged sword. first of all, take all opinions to heart, and analyze them. second, figure out of this particular thing does apply to your case.
Flipping animations in your case is fine. the sprite is symmetrical, aside from the shirt logo, which can be added on top of the mirrored one if you want.
the more complex your animations become, the less inclined you will be to manually redraw them instead of simply flipping.
you can see this in a lot of games, where they switch sword-hands when turning around, being the result of flipped sprite-sheets. its not bad practice, its efficient. Its not accurate, but most games get away with it.