@Game_ThruzOh i thought you tested it, cause of your previous post.
Anyways, i think it's not possible.
Cause i think the Bayonet will count as a melee Weapon. So, as you see on the Codex descriptions below....
•Forest Combat Codex: Get through the forest without any melee kills!
NO melee kills allowed, and if the Bayonet count as melee so it's not possible to do in one run together with the other Codex. Cause you need to fight the enemies offensive.
•Guiding Bess Codex: Get through the forest undetected!
If the enemies shouldn't see you, so you running best with melee kills! But if the Bayonet wouldn't count as melee, you could use that to kill them too. I personally think if it would be able to use the Bayonet, you can not finish it that easy. Cause the Soldier is screaming while the Charge, and the enemies will hear you running.
My opinion:
Do it in two runs! (Easy Mode) 😉
Any you can try a Bayonet Charge on the mission beginning, and see in your mission menue if it shows that you can't finish that one Codex in this run anymore cause it was a melee kill....or not.
Then you know it!
Greets,
Travis