1) A lot of stuff was moved over from the wiki, + it's extra work to create one, + it relies on the software being in a repository.
2) No. Ones from Debian for x86 machines won't install, for example. *_armel.deb might work, but generally the deb will need to be Maemo-specific. Certainly to show up and be installed in the Application Manager normally, a set of criteria need to be met.
3) No idea. Contact the Nethack port maintainer?
5) See Tools > Log...
6) Yes & yes. (to malware Q)