looking to develop an online job portal

I will be including user accounts, their profile data storage (including resumes), employer information (including photos of office premises), employee profile matching (with job opening by employers), dynamic suggestion box module for skill specific learning, an open chat module between employers and employees and possibly the availability of web crawling to gather raw data for other web functionalities. Considering I want to make it as dynamic and interactive as possible, their might be multiple asynchronous database requests causing performance related issues.

I have a couple of queries regarding what technologies to use for web and mobile application for this project.

Could you please recommend an ideal open source stack/framework(RoR, Python django, MEAN, LAMP) or even a CMS solution (Drupal) which has an active online community and sufficient open source documentation. Also, one that has libraries and APIs to incorporate all of the above features and more with minimal performance or scalability issues? Please also mention a learning curve estimate if possible considering the fact that I am relatively new as a full stack developer.

On the mobile platform, please suggest an open source framework as well (possibly one that compiles to native and can be ported to both iOS and Android) with minimal compatibility and technical issues (I've had some previously with Worklight).