Ahh okay, gotcha.
Session retention is do-able with any of the languages. I’m unaware of any out-of-the-box solutions, although what you describe is often found in the learning process (maybe try Google “session control” or similar keywords). It’s more a method than an application per se.
I understand completely what you mean about biases when it comes to the available languages. Python is considered a “strict” language and Python users belittle PHP constantly. My take on it is that if something gets the job done then it’s a good tool to use. Best to keep our options open than to jump on somebody else’s bandwagon simply for the bandwagon’s sake.
A session-based system is probably easiest accomplished in PHP (and will be quickest to learn by a long chalk). If you have a bit of time up your sleeve then Python or Perl are definitely very good options if you are considering advanced programming in the long term, but they’re probably overkill for something like this.
In consideration of time constraints there are likely plug-ins available for apps such as Drupal or WP that you could use. What you’ve outlined actually reminds me a bit of squeeze page type setups. Hopefully someone might drop by, read your requirement description, and post “Hey! Install WP and grab this plug-in and then do this…”