I remembered reading a good thread on alt removal, and when I pulled it back up, I noticed you had posted on that one as well. If you reread this thread, it appears the removal is not a really tough job if the bracket is removed along with the alt (working from underneath). I've not had to do this job on mine, so I can't confirm that. But I will definitely try it that way, if and when my alt goes south.
I've removed the pulley from the alt on my Caravan using a home-made removal/installation tool. This turned out to be just a moderate job, and actually quite a bit easier than I thought it was going to be. The tool that I built for the caravan used a drilled-out coupling nut for the outer, and a standard socket w extension for the inner. I would expect that the same type of tool is needed for any pulley - basically an "outer" hex sleeve which "keys" into the pulley, and an "inner" socket (likely 10mm) which turns freely within the outer sleeve. The outer sleeve needs to extend out of the pulley far enough to be able to get a wrench on it (to provide the countering force). Just a matter of finding something that works for the specific dimensions of the Aveo alt and pulley.