Is there a way to get growls from voicebanks - Solaria in particular?
If you search for growls in the forum there are a few threads that people have made scripts for growls. I guess you’d have to learn how that works. Haven’t tried it myself.
I did, but there’s an error message when trying to install.
You may need to ask in the thread where you found the script. That’s beyond my knowledge, sorry. I hope you figure it out 
Here is one of the links - take a look at how the script is written on that page and whether it matches your error script. If the content is different ´, then you downloaded the script incorrectly. You have to go to the label “RAW” and press the right mouse button and select - “Save link as” and the downloaded script should have worked.
Used Google translator to answer.
「いいね！」 1
In synthv AU plugin, some scripts get errors.
Other DAWs also have this bug maybe.