Wow what a great thread. Anyway here are my respones...
1) I've worked with all of them, but in order of current use, I'd have to go PHP (70%), PERL (25%), JSP (3%), ASP(<2%), Cold Fusion (almost never)
2) I prefer to use PHP and PERL for programming mostly because the syntax style is so similar they're practically the same language. I find PERL to be great for high traffic web sites (especially mod_perl) and PHP to be great for most of the other web sites (Medium to low traffic sites). JSP is extremly powerful, but I find it's syntax foreign, and I don't like using ASP and Cold Fusion as both require proprietary technologies to run. Anyone can set up an Apache box regardless of platform, but you need Windows to run ASP, and server support for Cold Fusion
a) I find that your code and server configuration are usually the security problem more so than the language you may be using. Although imho, patches to the languages are much faster with OSS than with Proprietary technologies such as ASP and CFM.
b) For me PHP and PERL are easiest to use, but I think that's just because I use them so often. I think in general, the language you use most will be the easiest to use. BUT I would like to say that the online documentation for PHP is FAR AND AWAY THE BEST I'VE EVER SEEN FOR ANY LANGUAGE!
c) PHP and PERL have great platform support
d) Here I think PHP is far and away the best, with native support for mySQL, SQL Server, Oracle and DB2 (plus a few others) along with the ability to use ODBC make it, again imo, the best for DB support.
e) PERL wins here. Of course I grew up on PERL so that interface seems intuitive now. I find PHPs filesystem interface a bit of a kludge and PERL to be more Unix like.
f) PHP and PERL in my experience, although Java support is pretty good now as well (for JSP).
g) I like the error handling in Java (JSP). It seems so very elegant and I've never been able to get a decent custom PHP error handling function up and running. I also like PERLs error handling as well.
4) I find that OSS languages (PHP, PERL, etc) are by far and away easier to work with, easier to find support information, and have a larger support community than ASP, CFM and the like.
Hope this helps and good luck with your report!