Matt, all pulleys are easily accessible even with the radiator in place and are easy to swop out with out damage if you are handy with the tools.
Regarding belt issues, prior to the guy damaging your alternator pulley, if the belts and pulleys are in good condition then the belt squeal would definately be a tension issue.
I have a spare alternator pulley if you decide to go down that route.
The alternator pulley can also be swopped out in situ. but it is no big deal removing the alternator if you prefer the alternator on the bench.
If he has damaged the alternator as well then don't worry as I have one of those as well.
Alex.