If you’re interested in trying to answer that question, you can click the link below where I discuss this topic in regards to different sects of the cast. Not only can you share your thoughts the parties I built in these posts, more importantly you can also comment your own ideas for what character classes they would be and create your own party of these same characters. I encourage everyone to really get creative and have fun with this. And make sure to look out on Tuesday morning for the final thread.
The Mane Six: https://www.fimfiction.net/group/41/crossovers/thread/497225/what-dd-classes-would-mlp-characters-be-pt-1

Starlight & Co.: https://www.fimfiction.net/group/41/crossovers/thread/497857/what-classes-would-mlp-characters-be-in-dd-pt-2.

The Young Six: https://www.fimfiction.net/group/41/crossovers/thread/498055/what-dd-classes-would-mlp-characters-be-pt-3