Traffic shaping using an E1 Connection Line with assymetric 2Mbps connection

[kirlox_kitoy]

HI everyone Im using 1.2.3 pfsense firewall i used traffic shaper to shaped traffics between our local area network well i've read the calculations and try to test it on our network, First of all I would just like to ask for your good advices if 2Mbps is sufficient for all 50 or more persons
that uses the following

1.)simultaneous web browsing e.g facebook and other social networking sites
2.)Web Scraping and crawling applications

And also if i get an error, such as a no parent error on the traffic shaper queues will the pfsense function still as normal.

Hope to hear from you soon.