What should I expect if my return was filed and accepted, but now I have a notice that requests more info?

The information on Where's My Refund is from the IRS. So you will have to wait until you receive your letter from them.  You could set up an account with them and you may be able to see what they are sending you.

IRS Individual Online Account  

• Taxpayers with a Social Security number or an Individual Taxpayer Identification Number can create or access their IRS Individual Online Account to get information they need to file their return.
• With an IRS Individual Online Account, people can:
• View balance owed, payment history and schedule payments.
• Cancel scheduled payments.
• Get transcripts.
• View or create payment plans.
• See digital copies of some IRS notices.
• View key data from their most recently filed tax return, including adjusted gross income.
• Validate bank accounts and save multiple accounts, eliminating the need to re-enter bank account information every time they make a payment.
• View, approve and electronically sign power of attorney and tax information authorizations from their tax professional.