My older son has a non-Apple phone with SMS/MMS. He also has an iPod Touch currently running iOS 5. iMessage is configured with his Apple ID and he's able to communicate with his brother's iPod Touch and with our (wife's and my) iPhone 4Ss.
His contact card on my phone has a "mobile" number and an Apple ID email address labeled as "iCloud".
What I have experienced is this:
- two separate threads in my Messaging app, one to/from his phone, the other to/from his Touch.
- I can message each separately by opening the respective thread in Messaging
- When asking Siri to "Tell <son> I'm on my way home", she'll use whatever thread he last messaged me on.
- If I ask Siri to "Text <son> mobile", she responds "<son> doesn't have a mobile number".
- If I ask Siri to "Call <son> mobile", she'll dial without complaining.
Maybe I need to try removing his contact altogether and re-adding it, and wiping out any existing message threads. Any other suggestions?