Interesting situation, I tend to say yes it will count. You can see it in the debriefing score table, but is a very unlikely situation so I don't know and I have played hundreds of sessions.
I got downed by a hunter when solo he was on the smallest bit of health when he ran up and melee,d me , My turret finished the job just when he killed me , and i did not get the kill.?. So i say no ..
Skill kills don't count. Checked it with commendations. I had to kill 5 hunters for some Survival commendation, and after 7 full Survival sessions and two skill kills, the game registered my 5 armed kills as an achievement.