I think the problem is/was with the bg2 fixpack, but looking at the readme there (v5, jan 28 2008) suggests any incompatibilities have been dealt with on the fixpack side - just in case you're unaware and go ahead and do something needlessly!
I think that was possibly the only issue - are the items you mention in the unfinished business readme the only ones this component covers, i.e the giving Simyaz his sword back in underdark, some anomen stuff etc? or are there other even less impactful changes that are included - point being if it's only those listed i've never seen/heard of any other issues coming up - just that glacias charm one, which as i say fixpack seems to have dealt with in terms of incompatiblity, so it might just be okay to install anyways?
I dunno, i'll let someone who's definetly in the know answer!