The Nikon D5*** series sounds ok, body + kit lens is around 2.5 now very user friendly and LCD screen can be flipped out for more convenience.

Extra lens would be 17-50mm from Tamron for around 1.5k (new) and perhaps get the 55-300mm for long range shots during company events like company dinner

Woah, RM10k for a casual DSLR is really a lot 
I agree with agito sifu, I would recommend getting the D5300, which has all the features you need, the 360 screen will be most useful for video and selfies too! 
I think the DSLR can be paired with a Tamron 17-50mm f/2.8 VC, which is a pretty good lens. I think it will be good to invest in a flashgun as well (Nikon SB700 may be a bit overkilled, but the reliability and quality is definitely there) for indoor shots.

Save the rest of the money for something else 

best possible go to times square nikon center there test holding for 5k series first.

because you mentioned many non-professional will use that. actually 5k series is very light and small body, someone with big hand will not like that XD

lens i think kit lens good enough la (for beginner)  
you might need get 1-2 spare batteries if really do for event. or maybe buy another body i duno la how many people in charge in photograph for 1 event. 

5d is cannon dslr 
cost you around 8-12k if not mistaken just for body alone