I think the exact set of choices you need are:
- Tell Rachel to take some fighters into the woods. This isn’t necessary to kill everyone, but it’s likely someone will die without it.
- Attack first.
- Shoot Natalie.
- Search for Benton. This needs 70 search skill, or 50 if you have built a sky nest.
- Shoot Benton. Essentially your ranged weapons skill plus your weapon’s mod value has to be greater or equal to 120. The mod values for weapons can be seen on the stat page. Suppressor increase mod value by 5, suppressors increase it by 10. You specifically need to shoot him at range, attacking him up close is easier but won’t kill Wyatt. It’s impossible to kill Benton without at least 80 ranged skill.
- Wyatt should be killed while trying to shoot you.
- Keith should leave at this point. He’ll call out to his group even if they’re dead.