Hi legend-ary and welcome
I too switched from a Yaris to a Mk1 Jazz back in 2008. Haven't looked back ever since, and now just recently upgraded to Mk2 Jazz.
Talking about headrests, the ones on ebay look different to the ones shown in your photos. Yours has a technical fabric, whereas the ones on eBay seem lined in a felt-like velour fabric.
Why not have a look on auto trader, most of them have interior photos, which you could then use to compare between 2004 and 2006 (2005 updated / facelift) models.
Btw, you car looks really nice and clean.