Will I be able to make calls with the new iPad Pro mini?
If you have an iCloud account, an iPhone running iOS 9, and an iPad Pro 9.7", then yes, you can make phone calls on it over the connection with the iPhone. The iPad is not a phone, so it handles the calls over its Bluetooth connection with the iPhone. Go to Settings/FaceTime and turn on the Calls from iPhone switch.
When you do this, iPhone incoming calls will ring on both your iPhone and your iPad. To make a call, click on any phone number in your Contacts app, or just tell Siri to call a specific phone number. It will send the command to your iPhone and place the call, allowing you to use the speaker/microphone on the iPad to talk.
This feature will also work with your Macs and Apple Watches, once it's activated.