From what I've read about both over the last few days is this...
Yes onstar is available in the new Adam S, it is not anything to do with Apple Car Play/Siri, this is what it says on the configurator:
"Your personal connectivity and service assistant which connects you to a qualified advisor, at the touch of a button, 24/7:
A) Automatic Crash Response: In the event of a crash, an OnStar advisor is automatically alerted who can notify emergency services, if needed.
B) 24-H Emergency Call Service & Roadside Assistance
C) Smartphone App: Check your tyre pressure & locate your car – remotely via your smartphone.
D) Wi-Fi Hotspot: Your car is Wi-Fi ready! Soon you will be able to enjoy the benefits of fast & stable Internet access onboard
E) Stolen Vehicle Assistance: If someone steals your car, OnStar helps you get it back.
F) Vehicle Diagnostics: OnStar can check key car systems like engine & transmission remotely.
G) Destination Download: At the touch of a button, an OnStar advisor can provide you with any address you might need.
H) Some features may not be available in your region, for your carline, or trim level. Go to
www.opel-onstar.com for a current overview of potential restrictions.
I) For more Information see www.vauxhall-onstar.co.uk"
The intellilink we all have already, isn't ready for car play and all our phones seem to be doing even though the update is on our phones and we can do all that but we should be able to get like our phones on the intellilink screen, so we can use certain apps like Maps and Spotify whilst in the car.... A combination of intellilink/onstar/CarPlay should be possible all the minor bits are there and it all just needs to come together into one package.
Intelilink has always come with 'Siri Eyes Free' this is when you connect your phone via BT to the car so you can call and text. What has possibly happened is, we have all bought cars thinking/knowing CarPlay is round the corner and should be something we should be able to get (in the near future) however I don't see "CarPlay" being in any Adams for the foreseeable future as it would cause Vauxhall to have to go out of their way to do something for existing customers where they are more concerned about new customers buying cars rather than helping us improve their cars to make their new cars better