Bayonet kills in BF1 - Melee or not?

Thanks.  I'm trying to get both codexes in the level and I was hoping it wouldn't count as melee.  Is there anyway to kill all the Germans without using melee and without alerting them?

Is there anyway to get both codexes in one run then?

Third mission, Fog of War, one codex requires the player to kill all the Germans without raising the alarms, which as I understand it means you have to melee them.  The other codex requires the player to not use any melee attacks.

So I'm wondering if it is possible to do both in one run rather than replaying the level, hopefully by some attack that's a one hit kill and if done right won't alert the other guards, and isn't melee.

I thought the bayonet charge might do it because you're not just whacking someone on the head like a normal melee attack...

That's exactly the mission and the codexes I'm trying to do.

I figured if the bayonet running kill doesn't count as melee since it doesn't look or act like a normal melee attack it might be possible to get both in a single run, since as long as you bayonet the guards before they see you they don't alert the others.