Here's a version of the picture above that you can import into Kolourpaint or whatever image edition software you use:

I'm also including the palette I believe Canvas '26 will use.

Most letters are 5x3. A few are 6x3, 5x4 or 5x5. In a lot of cases you can shave off one or two pixels, at the expense of making the letter look less nice, or misaligned. For example Cyrillic ⟨Ґ Ц Ç⟩.

For most diacritics the least bad solution I found was to reduce the base letter to 4x3, then add the diacritic in a separated line. Note you can however use colours to your advantage; if you paint the diacritic in a medium grey you could either make the base letter or the letter+diacritic pair 5x3, by letting the diacritic touch the letter.

Worth noting there is no "right" way to draw letters in pixel art; I'm sharing one among many, but if you have your fav, go for it.