Can I use the same bootable drive for all models?
The general rule is that you cannot boot a device using an OS older than the device itself.

So the chances are small.

The trick would be to recreate that drive as the latest OS update is announced, concurrently with that product release.

Alternatively, use the Apple Migration Assistant

Extract:  


  Before you transfer information from a Mac, connect the two computers with a cable (Ethernet, FireWire, or Thunderbolt).
  
  Note:   If you’re transferring from a Mac with OS X v10.8 Mountain Lion or earlier using a Thunderbolt cable, follow the steps for transferring from a Time Machine backup or other disk. 
  You can also transfer information over a wired or wireless network, as long as your computers are connected to the same network.
  
  Open Migration Assistant, click Continue, then follow the onscreen instructions to transfer info from a Mac.
  
  
  Open Migration Assistant on the other Mac, then follow the onscreen instructions to transfer info to a Mac.
  Select what to transfer.
  
  
  Apps: Select the Applications checkbox.
  Incompatible apps or apps with newer versions already installed may not be transferred or may not be usable.
  Computer settings: Select the Computer &amp; Network Settings checkbox.
  Your desktop picture, network settings, and more will be transferred.
  
  To begin the transfer, click Continue.