Is there a Streamsaver plan for those Rewards customers who get free Peacock?

I would doubt it. The free Peacock promo is a hideous mess with your Peacock account permanently locked to Comcast, and no ability to upgrade to ad-free.

I will take this further and ask what about people with peacock and Netflix included ? 

Hello @Robster2001, thank you for taking the time to reach out on social media.  I understand your concern, and I'd like the opportunity to check into that for you.

To access your account, will you please send us a direct message with your full name and complete service address.

To do so, click on the chat icon located at the top right of this forums page.

Here's the detailed steps to direct message us:

• Click "Sign In" if necessary
• Click the "Direct Message” icon (upper right corner of this page)
• Click the "New message" (pencil and paper) icon
• Type "Xfinity Support" in the to line and select "Xfinity Support" from the drop-down list
• Type your message in the text area near the bottom of the window
• Press Enter to send your message

The official answer from the direct message:

"[W]e do not provide any additional discounts or offer for a cheaper/different service for customers that already have a complimentary subscription to Peacock. The Xfinity StreamSaver Bundle would be $15.00 per month for the three streaming services."

Cool.  I won't be buying it, then.