For the checking of archived websites, I thought it might help to use some add-ins, to gain some time, you know?
Now, I don't know if there's a real add-on for this, but there are sites (spiders) like this one or this one (the latter seems more accurate) that could crawl a given page in the archive and check it for broken links. That's to say, so long as the page isn't protected through a robots.txt access control file. Also, links that are counted as broken don't reply within a given time, so they could still be working.