Having a quick look you should be able to export the ‘questions’ via /wp-admin/export.php
As the plugin uses ‘Custom Post Types’ you should be able to then edit the exported XML file and find do a search and replace:
I had issues with the plugin on my site so I am not sure if it uses ‘question’ for the answers or uses ‘answers’ as a CPT for them, if it does use ‘answers’ then search and replace:
Once you have done that then import them back into WordPress and see how they look, no doubt there will be a few issues such as topics not associated with a forum and depending on how many of these you have editing them in bbPress topic/reply panels should help you fix up any issues, if you have thousands then doing some more tweaking in the XML would be your best bet.
To get an idea of what you would need the best idea would be to export some bbPress forums, topics & replies and have a look at the XML and this should help you work out what values you need to use for search and replace.
Awesome! Thank you so much for your help!