Dear members,

Watch out, long post!

I normally create very basic websites in wordpress (PHP/CSS/HTML and just a bit of js).
Lately, someone has asked me to design a site with specific functionalities.
Since I have not much experience in this type of work, I wanted to get advice from some professionals.

They need a website, where users (store managers) can upload pictures of shoplifters with details and all, so the other users (shop managers)
are aware of possible shoplifters.
I was wondering whether wordpress is suitable for a project like this. Perhaps you know a better CMS or script...

The idea is that when users visit the site, they have to login.
then they'll see a page with 'visualized posts' or images (that are linked) to a post that contains more information.
There should also be a news feed.

That's all the info I have.

4 things:
1. Security -> Is the normal Wordpress login platform good enough for a site like this, I dont see why not, if not is implementing a 2nd code (by text or other way) a good idea or still not enough.
2. Posts most deprecate -> I'm not sure about this, but can I create categories (1 month / 6 months / 1 year) and change the code in a way that posts who have 1 month as category, get deleted after one month ? Or do you have an easier solution?
3. Users must be able to fill in a form and send it to the police, do I need extra security measures for this form except recaptcha. (the client wants SSL).
4. Responsiveness is important.

In conclusion:[*] Do you guys think Wordpress is suitable , if not what kind of CMS do you suggest for this.
[**] Do you have improvements for this project ?