i concur with the power steering leak taking out your alternator. That correlation certainly was the case for my 95 LS400.
from what i hear the most likely cause of the leak is the O ring that seals the connection between the power steering fluid container, and the pump that it goes directly into, which is fortunately not too advanced of a DYI job and the part isn't expensive. thats the best i can say on that though.
Also welcome and congrats. I myself sure wish to upgrade to a 98-00 ls400 for the new features and engine power that was added.