I have multiple thermostats.
You have several questions - will they work with your system - the nest information you received from nest should be your guide here.
Can you control them from ST - yes, with NST Manager [RELEASE] NST Manager v5.0 and http://thingsthataresmart.wiki/index.php?title=NST_Manager
What automations can you use - There are a lot of choices with Nest - Alexa, Google home, Smartthings, etc. With Smartthings there are many thermostat SmartApps available, and many automations built-in to NST Manager itself.