For the missing characters, the problem is probably the font used by dictionary application.
the font is Liberation Sans, the default one for the menu. The problem is:
1) It's not an all-purpose Unicode character, so it doesn't embed all the glyphs for many languages. that's the squares.
2) No matter if you change the default font with one of your choice, because in the dictionary app it doesn't change, which is why I guess the font is directly called by the application executable.
Atango suggested a procedure in this thread:
https://www.mobileread.com/forums/sho...d.php?t=131180
so he solved his issues with Korean dictionary and customized Korean menu.
For the collates.txt problem, could you please post your collates, keyboard and morphems.txt?