I think that the best way to answer this question would be to recommend that you acquire a good reference grammar and acquaint yourself with Babylonian Talmudic Aramaic. To that end, the most readable is certainly the one by Yitzhak Frank, though I prefer the one by Alger Johns, even though it's technically for Biblical Aramaic. You might also want to look at M.H. Segal's Grammar of Mishnaic Hebrew. If you do, you'll see that the Hebrew of the Mishna, the Tosefta, the tannaitic midrashim and the beraitot is all very influenced by Aramaic, in terms of grammar (the construction of individual words), syntax (the construction of sentences) and orthography (spelling).
That's so far as your second question is concerned. So far as the first is concerned, there is variation between לְךָ and לָךְ even within the Hebrew of Tanakh, specifically when the referent is masculine. Unless you are able to provide an example that indicates otherwise, I imagine that is the situation here too. It has nothing to do with the difference between Hebrew and Aramaic, but reflects merely on differing orthographic conventions. Likewise, you will see masculine plurals in the Mishna alternating, even within a single mishna, between possessing a final mem or a final nun.
I cannot speak for the vocalisation of ArtScroll, but there is a vocalisation tradition for the Mishna that is well established. In fact, there was even a system of accentuation at one time as well, with Tiberian te'amim, such as we find in the MT. You can see manuscripts of the Mishna, some of which are vocalised, at this site.