"Can you use steering wheel button to send texts or update calendar? "
Now really, how would one button be able to send, create, save, or do anything else to texts and calendars, that require more input than one button can provide?
The base "radio" in the car can connect to phones with Bluetooth but you don't get the same range of functions that the full nav/telematics upgrade package gets you. Which still may not do what you want.
Your best bet is to visit the dealer and see exactly what does and doesn't work, because even Audi-US isn't very familiar with the systems.