[Quoth]

I use Caps Lock Key for Compose and Dual Shift, either Shift cancels for ALL CAPS.
I think Compose is an ancient UNIX/Solaris thing, though AltGr now makes many of the accented characters simpler.
You could add Cyrillic to .XCompose and there is a standard map layout for QWERTY.

There seems to be no need to put HTML entities for “”‘’°′″—…– etc when using UTF8 in ebooks. Conversion of epub2 to mobi and azw3 seems OK too. Non 7bit ASCII may not work well in either pdb format for PalmOS.