Oracle APEX stress test, integration with facebook, google, payment system

0. Crom job to automatically renewed certification.(probably I will need a guide). 1. I will prepare of production environment with 4gb RAM, 2CPU and 25GB storage. First of all, I will add some structures and data to tables and next we need to do some stress test how many users can works in the same time on Oracle XE. 2. When user try to registry then should be sending email with confirm(unique link, after clik by end user account will be confirmed). SMTP is configured and working correctly, point require generate unique link only. 3. When user exists can do recovery of password by sending email with unique link which redirect to page in APEX where changing will be allow. SMTP is configured and working correctly, point require generate unique link only. 4. Registry by social media(google, facebook). Prepare Package to integration in PL/SQL with function login, logout. Proposal of user table which will be cooperate with traditional registry by email. 5. User will can add some photos and files in application, do you have any better idea than save it direct in database? Maybe external server? Require is prepare package to manage files(save file, remove file on remote serwer). Prepare structure to storage path in oracle. 6. Integration with payment system. Probably [login to view URL] but we will see. First of all point 1. I need to know how many users we can handle and then I will make decision about others point. Points 0,1,5,6 is necessary. I will no needed any guide/instruction regarding to developing, but if you will do some configuration of database(e.g. ACL) or centos then I need from you list of command to do the same on production environment. More than less I will do by myself regarding to implementation but it is possible that I will need at the end your help with implementation your changes on production.