Do you think functions such as mehndi/mayoon be part of our marriage ceremonies?

No, these are Hindu 'rasms' (traditions) and should not be part of our culture.

Yes, why not? There is already a dearth of fun events, why should an opportunity to have fun be missed? Who cares about religion or faith or whether dese r islamic or not? we are muslims by name, isnt that enough?

No, not only because these are Hindu-istic in nature, but also the songs/dancing/mix gathering of ladies/men, and lack of hijab is way against Islamic rules, not to mention the 'israaf' (waste of time and money just for fun) which is also haraam in Islam.