SA 4 doesn't have an update notification mechanism, but SA 5 will, so you'll be able to hear about future updates.
The editions have largely been merged, so if you have a support and upgrades contract, you'll be upgraded to whichever edition yours has been merged into. You won't lose any features due to the licensing change if you have a support and upgrades contract.
If you can create a small example of the resource combining problem you've found, I can make sure it's fixed before the release (if you get it to me soon enough). Send it to support at redgate dot com.
Red Gate .NET Tools