4) There is also the authoritative position of the Arizal (whose teachings are from Eliyahu Hanavi), that all of Hevel’s gilgulim need Tikun through death (like he himself needed), and the Ir Miklat is Michaper and Misaken for those who kill them unintentionally. If we merit that Mashiach comes before “its time” which means before the Tikun is finished (when there won’t be any death at all since ??? ???? ????), there will be a need for (even more) Arei Miklat (and hence the word “??”). But if Mashiach comes in “its time,” after the Tikun is finished, there will be no need for the Arei Miklat. Either way, there will not be any intentional killing and the unintentionall killing will fit into the “Ina Liyado” in Makos 10:2. The Arizal is quoted by the Zayis Raanon and the Maskil Lidovid.
5) The Maskil Lidovid also cites the Shalah. The Shalah proves that not all of the great successes prophesized will be at one time, there may be different periods, but eventually, there will be no death at all.
6) The Alshich offers a similar explanation as the Arizal.
So in response to your question about the Malach Hamaves, maybe Hashem will Shecht the Malach Hamaves after people finish killing unintentionally, after the Tikun of Hevel is finished, at a later period.
And a person with ????? ????? can ?”? be mafsik someone from Torah and then let the ???? ???? finish the job.
But you may be right, since I have no idea what the Malach Hamaves is and how it works.