Hi zoochie,
Re: "Help with Siri responses—I ask on iPad and Siri answers on a different device"
As it seems saying "Hey Siri" is alerting Siri on the iPhone when you are using iPad Pro:
Wondering if you may be able to press a button on the iPad Pro instead, to get Siri's attention
Eg: Apple support's article: Use Siri on all your Apple devices - Apple Support
says you can:
"Press and release the button
- If your iPad has a Home button, press and hold the Home button, then make your request.
- If your iPad doesn't have a Home button, press and hold the top button, then make your request.
- To make a longer request, press and hold the Home or top button until you're finished with your request."
Else: if needed: you may want to contact Apple for accessibility support - Apple Support
See: How to contact Apple for accessibility support - Apple Support
or
Apple's Accessibility Support Website:
(NB: You can "Get Support" from the link at the bottom of their website:)
Accessibility Support - Official Apple Support
All the best :-)