@Analogus,
As far as I know the font files used by epub are different (and always have been) from those used by txt/lrf/rtf. Overriding epub fonts is done by creating one or more .css files (containing lots of @font-face statements) in the folder /database/system/PRSPlus/epub which can be accessed and changed via PRS+ as desired.
I think '*nix-line break' means each line ending in the file is Unix/Linux style
LF only rather than the Windows
CRLF or the Mac
CR
Edit: To use the same set of fonts for everything,
the wiki (last section) gives an outline