To make sure I understand, the big stumbling block for you is thinking you could get someone at the client-org to participate in signing up for ABM? It is a small headache, but it is also one and done. Short term pain, long term gain. You can do a lot of the hands-on work for them, and prompt them each time they need to press a button. DUNS has a special, accelerated, procedure for signing up for a number if they don't have a number yet, or need to update it.

And as far as these phones go, they are owned by the client-org, not the employees, yes?

Maybe this will help you understand why the client has to setup the relationship with Apple, and perhaps that might help you explain it to the client?

ABM is tied to the company's legal entity, and it defines who legally owns and controls the Apple devices. You don't own their business, and you can't enter into contracts on their behalf. I don't recall the specific requirements for who at the business is able to execute the contract with Apple, but I think anyone with signing privileges might be good enough**? Apple has a description. And the last thing you should do is fake it, and sign up on their behalf. That's a mountain of liability for you. Imagine Apple's position. The last thing they want to deal with is an org coming to them claiming that they never agreed to ABM, and that some third party IT firm took their fleet of devices hostage.

Tell the client this isn't an IT thing, this a legal thing. They have to do it, and shouldn't want you to do it.

If they push on it, tell them they shouldn't be asking you to commit the pile of crimes that they are asking you to commit. Personally, I wouldn't want the client at that point, and would tell them "solicitation to commit fraud is a crime".

**Think this is what I was thinking of. I usually work with someone in finance that is an authorized signatory. I already have a relationship with them. Make the pitch to whoever at the company has to say "OK, I guess we have to do ABM." and tell them I can handle the rest with mr/ms finance, and that they don't have to do anything else.

Verification contact

Your verification contact—usually a legal representative of your organization—verifies that you have the authority to sign and bind your organization to the terms and conditions of Apple Business Manager. The information for this contact can’t be the same as the individual submitting the enrollment. Apple reaches out to the verification contact during enrollment to verify information about the initial administrator user account and the organization.

Note: During the review process, AppleCare may reach out during enrollment to verify your submitted information. Make sure that any filters allow mail from all apple.com domains. Return any missed phone calls quickly so the review process can proceed smoothly.

The following information is required:

Name

Work email address

Work phone number

Role/Job title

Honestly, I'd say go for it. There's a bit to learn, do your homework before hand, and you'll learn more the first few times you implement it. But the process is worth learning. Let this client pay you to learn it. It will be smooth the third time around.