As an update:

I got home and used id3v2 to convert all V1 tags to V2.[1] I then
stripped all V1 tags.[2] I removed all database files and rebuilt the
database. Thus, there should only have been V2 tags. The result was
the same three variants of Alanis Morissette (Morisette, Morrissette,
Morissette).

I then forced the tags to read Alanis Morisette, deleted the database
files, and rebuilt the database.[3] Again, I was faced with the same
three variants of Morissette's last name. I then listed all tags and
grepped for 'Alanis' to see if the tags showed any spelling
variants.[4] There were no spelling variants.

Finally, I again deleted all databases, shut down the player, booted,
rebuilt the database and rebooted. Still have three Alanises (Alanii?)

Is there any way to pry open the database and force a change? I mean,
if it were in something like sqlite format...

-- 
Ben Wilson
"Words are the only thing which will last forever" Churchill
[1]: Using ZSH: for f in **/*.mp3; id3v2 -C $f
[2]: for f in **.*mp3; id3v2 -s from within the Alanis directory.
[3]: for f in **.*mp3; id3v2 -a 'Alanis Morisette'
[4]: for f in **.*mp3; id3v2 -l |grep 'Alanis'