Are Halo MCC Achievements based on personal performance?

With the campaigns of the available games done, my friend and I plan to tackle some of the extra achievements.
I.e. "Look Out for the Little Guys", which requires to complete Two Betrayals on Legendary without killing any Grunts. If we jump into coop and he kills all grunts while I concentrate on other enemies, will I be getting this achievement? Similar to "Leave It Where It Lay", where on Two Betrayals on Legendary, we are not allowed to pick up any new weapons. If I pick up any weapons while he keeps the starting weapons, will he be getting the achievement?
So can one player in the session work on an achievement while the other player "ignores" it?
Pictures about "Are Halo MCC Achievements based on personal performance?"



Can you get achievements in Halo MCC?
The Halo Reach: Campaign Add-on for Halo: The Master Chief Collection has 91 achievements worth 920 gamerscore. Halo: Reach: Complete Winter Contingency.How long does it take to get all achievements in Halo MCC?
How long does it take to beat Halo: The Master Chief Collection? The estimated time to complete all 400 Halo: The Master Chief Collection achievements is 300-500 hours. This estimate is based on the median completion time from 184 TrueAchievements members that have completed the game.Why am I not getting achievements in Halo MCC PC?
There are some known issues regarding these achievements not unlocking immediately upon completion. In most cases they are granted within 24 to 72 hours after completion if they aren't granted immediately. If you have not received the achievement within 72 hours, please visit the Halo Support site and create a ticket.How many people have every Halo MCC achievement?
If we're going off trueachievements' stats, around 1767 people in the world have every achievement in the game.HALO REACH MULTIPLAYER ACHIEVEMENTS | MCC Achievements Guide for FAST \u0026 EASY Achievements!
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Aidan Roof, Nick Mark Mayer, Julia Larson, MART PRODUCTION