Can we un-install non critical applications and add our own?

Question

Can we un-install non critical applications and add our own application in Ubuntu 14.01 and then redistribute and sell it to people over the web without any legal issues?

Answer 1

Short answer: No.

"Ubuntu's trademark policy prohibits commercial redistribution of exact copies of Ubuntu, denying an important freedom."

http://www.gnu.org/distros/common-distros.html

There may also be proprietary software that you do not have the legal right to redistribute as well.