I've been a Chevron employee 40 years. Started with Gulf Oil so I have been through mergers , re-orgs and all the down turns in the Industry.
I would think that Chevron management would be capable of handling this critical time without the help of outside consultants. They have had plenty of experience over the last 4 decades. They could have kept this very simple and less stressful on the employees by just offering a voluntary retirement package for the " near retirement group of employees " and then cut the low performers and contractors. Keep it simple!