So I don't know if this has been posted anywhere else on the forum, but I found the video of Diane y'all were looking for.
It looks like the full segment to me, but there are some parts from southrn500's description that are missing, specifically the very beginning when she's wearing the tank top, and the part where they cut back to the studio. Fortunately, this clip starts when she's still wearing the bikini, and ends with her dipping in the ocean as seen in the caps from years ago.
The other thing that's kind of disappointing is the quality isn't the best, but considering this is from the year 2000 and the elusiveness of the segment itself, It's still pretty good to finally see this.
Also, you're going to want to turn annotations off, the uploader covers all of his videos with them for some reason.
hxxps://www.youtube.com/watch?v=QsAHjkc4zI8