When adding these devices to the house, can I have just one carbon monoxide alarm that will activate the rest of the smoke alarms if it goes off ?
This is not a feature of SmartThings. For these safety items you should rely on the ability of the detectors to work standalone, and then ST get notified if ST, your network etc are all working.
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For safety reasons, you should select a sensor model that has that feature built into it.
If you have the ADT/smartthings hub model, then their CO sensor does have this feature. But that device doesn’t work with the other hub models.
If you are using nest protects with the unofficial integration, they also have that feature.
The Z wave CO sensor that has an official integration with SmartThings, however, does not have this feature.
So start by selecting a device that already has the feature. And as @E_Sch
Mentioned then the feature should work even if the smartthings hub is not working, which is important for this class of devices. 
I’m looking at the First Alert z wave carbon monoxide and smoke detector and it works with smartthings. They also have a smoke alarm only that work with smartthings. I should have been more clear in my first post, but the question was if one alarm can trigger the rest ? Using smartthings or not.
Not that model.
If only there was a company that designed an interconnected smoke and CO alarm that had built in zigbee and the DTH built for SmartThings.
Some might say that would really be a “halo” product.
You mean died and gone to Heaven? 
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HAHA! Yes, of course.
I am hoping that I never have any issues with my DTH, or that I even have to remove my Halo detectors from ST, because I will never be able to add them back again!
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What models will trigger the rest when going off and also works with ST ?
Halo works stand-alone still. While their app is gone and they no longer are in business the detectors still work and will for their 10 year projected life. You can manually test them by pushing center button on alarm. Also if Carbon monoxide is detected it alerts all of them as they are interconnected. They work just like a dumb detector. I have 8 of them so too much expense to replace since they still work in ST.
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For what it is worth my halo smoke detectors do not continue functioning without connected WiFi and the native app has gone completely dark. Before losing the app I learned that the device was sending An alarm notification continuously alerting me that WiFi had been lost. Sadly I never had it paired to smart things and just used the halo app.
After a few days of being disconnected the detector sends a new alarm that the back up battery is dying and to reconnect it to power. This buys me some down time before it all starts again and I unplug it to move it far far away.