Ah, yes, that'd be it.
My bad!
That line worked like a charm, though; sprites inserted back in, and the Japanese text on the Challenge Mode rankings screen buttons is now fixed. I'll go through and finish up all the remaining text pages, and see what's left over after that!
Edit: Alright, so that's everything I can do at the moment... There's an issue with editing the text on the tabs in the scores page; the Japanese text that appears in the extracted txt files corresponding to the location of each tab does not reflect the actual text shown there. It's just gibberish like "papipupepo". Editing it anyway causes the pages to glitch out in weird ways:

As predicted, the Time Attack difficulty select does not have any translation, as the file that *should* have corresponded to the Time Attack difficulty select is actually Challenge Mode with the hidden difficulty unlocked - I'm frankly just not good enough at the game to unlock the Insane difficulty, so if any brave soul can test unlocking that difficulty in Challenge and seeing if the hidden difficulty appears and everything is still translated, that would be awesome.

While I was able to change the Japanese "Guest" to "None" for playing without a registered name on the Name Select page, it still shows Guest as the player name on the VS setup screen, and I'm pretty sure it'll save any high scores with that name too. So it will definitely need some deeper hacking to replace the Japanese default text.

The Records screen also wasn't displaying the translated text - I think this may be another case of multiple versions of the page existing, and I suspect that if you took a new 1st place score, the translated version would appear.

A cosmetic thing that would be nice, is if the notches on the score screen tabs that surround the big mode name could be moved, as the english text exceeds the width of the original Japanese. It probably wouldn't be too difficult to move the background tiles around... if I actually knew how to mess with existing tile mapping like that.

Here's the new patch; includes both title logos, and all the new translated stuff.
Kirby's Super Star Stacker Beta5If anyone can find anything that's been missed, this is where it gets tricky.