Import, Permalinks and Archive Issue

I recently converted from Movable Type to WordPress, and now I’m attempting the tough task of making outside links to the old posts jive with the imported files. You can see my blog here now: https://intheagora.com/

I was able to import all of my old posts but, as is often an issue with such a conversion, I’m struggling to get permalinks to the old posts jive with the new ones. More troubling, though, is that the archives all link to the old posts and old monthly list, even though I can clearly access these old posts now through WordPress and even though *the slug and permalinks are the same*. Thus, in the WordPress admin area I can edit an old post and tell it to publish to the same URL as the old post, yet only the old post remains at that URL.

This is truly a vexing issue. Any advice? At this point I’d even be willing to pay someone for help.