I am going to be dungeon mastering for DnD, and would find it helpful to do some live audio pitch mixing for some of the characters voices.
On Windows I would do this with Adobe Audition, any good alternatives to make this happen? Or run it under wine?
You will need to use the JACK sound system for low-latency realtime effects. QJackCtl is my preferred choice for controlling JACK audio, but I also use Patchage which has a nice GUI and easier for making audio connections between multiple apps
Ardour is best known and supported DAW, but there are better options to keep latency as low as possible for live audio
I would use a simple mixer like jack_mixer then add add multiple effects hosted in Jack Rack, and can have multiple instances of Jack Rack for different voice effects - Linux uses LADSPA (and LV2) plugins for effects etc similar to VSTs in Windows. This modular approach will take more effort to set up initially, but once you have some saved configurations to play with, makes it a lot easier to add extra effects and channels
Penguin Producer has a few examples of effects chains that should help you get started. Rest of the site also has great info on Linux audio/video production
KXstudio also has a nice GUI for patching ins/outs to other software using JACK. I don't know enough about other software to hlep. Just that maybe KXstudio might suit your needs.