Hi there, g2g2.

The email is correct, you need an intuit account as part of the security features within QuickBooks. 

The prompt log in using your Intuit Account ID happens when you open or create a new company file, add a user, sign in to My Company, or while accessing Intuit User Account Management. This login makes it easier to manage your connected Intuit services.   

You can go through the process and once it has been successfully set up. I'll show you how:

1. From the Intuit account window prompt, select I’m an admin, and I’m the primary person who can: then select what you can do in the account and enter your email. Select I’m not an admin, I’ve just signed in with the admin's credentials.
2. Click Continue.
3. If you selected I’m an admin, and I’m the primary person you’ll be prompted to enter your Email or user ID, then enter your Password.
4. Select Create an account if you don't have an existing account.
5. Click I forgot my user ID or password if you have and want to recover your account.
6. Click Sign In.

You can also check out these articles for more details with managing and securing your accounts: 

• Password security for QuickBooks Desktop
• What is CAMPs and how do I use it?

As for the second question, there will be no effect on the users since the admin is being effected, and finally for the third question, it does need to be the primary contact account. You can read further into that with this post.

• Change payroll administrator, payroll contact, or primary principal for Assisted Payroll.

If you have any other questions, feel free to post here anytime. thank you and have a nice afternoon.