Just an observation, but I've discovered that it IS possible to play Avara in classic mode with no mouse problems whatsoever.
The only way I've managed to get it to work is by using a graphic's tablet that also has a mouse. I've had this confirmed with a few other people (all Wacom tablets).
This led me to beleieve it was just the system's handling of mice that was to blame and tried running the mouse through USB Overdrive, but no luck 
Heh, this may be a known fact already and I'm just catching on, but if not, this is at least one solution.
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