In part 2 only two first repeats of rows 6 have two k2tog’s in them. Starting from the third time, row6 is worked sl1, k8, k2tog, k2, t+p etc. (only one k2tog in all three decreases in row 6).

In part 3 better to BO 11 sts, it will make the top edge of the mitten more even.

And when trying on the mitt in part 1, it should be more snug than loose, or you’ll have a somewhat blousy fit in the palm.