Hi There,
After going through the details I have only one question which is
Why have you chosen Joomla?
As WordPress is a much easier, cost effective, solution which has FREE plugins for all the features that you might think of.
Additionally CSS3 will be better with HTML5 ! So that the solution is responsive and optimized for all mobile devices.
Kindly do let us know your most valuable feedback on this one.
Best Regards,
Naved