Update:
08/22 I-751 sent via UPS to Elgin Lockbox
08/25 UPS said delivered to front desk and signed for
08/28 Text message from USCIS with Receipt Number
08/29 Partial Upload of evidence in online account
08/30 Receipt notice in online account - Biometrics notice just says "For some cases, we require biometrics (fingerprints, a photo, and a signature). If we need biometrics from you, we will send you a SEPARATE appointment notice with a specific date, time and place for you to go to" - Not sure if they will reuse my biometrics yet or not as I'm not sure if that notice would be under my documents on in the receipt itself.
Case is at NBC