in reply to
Is Perl the most adequate language ?
The language does not matter. You are saying that the programmers will be you and your friends, so use a language that you all know and feel confident in. PHP might be a very good language for websites but that doesn't help if you are a Perl guru and know absolutely nothing about PHP.
I also think that the answers you are going to get here will be pretty biased, as this is Perl website after all. Unless you ask the same question in Python, Ruby and PHP forums, you won't get the whole picture (and still... I somehow think that Python people are far more zealous about their language than anyone else)
My personal opinion (which is of course, biased) would be that PHP is an ideal solution for a small website. If you think big, then Perl would be my answer. But probably just because I know it more than any other language you mentioned.