If you're catering to just UUM students, you should a survey among them to see they what they prefer to play.

No point over extending yourself trying to cater to everyone and having so many different games, stretching your resources too thin. Less headache for you at the end of the day.

Since you've said that you're not that experienced in organizing a tournament, my advice to you would be to start small then as you get a grip on things over time, you can work your way up to organizing bigger tourneys.

Sample rules can be found easily online:
http://www.worldcybergames.com/6th/main.asp
http://www.caleague.com/
http://www.cevo.com/