well, I can't help you with the second problem, but for the first:
get the editor pack (IIRC its available at gp32x.de).
unpack the bor pak with paxploder
edit the levels.txt and remove lines that say something like "secret=1"
look into your chars folder. There should be a bunch of folders that represent each charakter that is avilable in the game (wether playable, hidden or enemy). Now look into each folder ad have a look at the textfiles in those folders. If a textfile says "type player", then remove anything like "secret=1".
repack your pak.