Could i suggest for a meet up/potential meeting point somewhere around Piccadilly gardens?
One of the most central points, most of the busses stop there, the trams stop there and if you travel to Piccadilly station you have to pass through it too get down to Deansgate. If you travel too Victoria its maybe not worth meeting there though as its closer to go straight to deansgate?
Im from manchester so i know it like the back of my hand and im happy to help arrange things, i live in leeds so will be getting the train on monday morning. So if there is anyone in Leeds who wants to travel with, i think some of us may be already.