Heres a quick map of some locations.

The red dot is where the rally will be (city hall)
The Black dot between City hall and Waterloo town square is a coffee shop... don't know the name, but I'll recce it today.
The Blue dot is a basement pub off of princes street called McMullens (good wings/pizza and beer deals)
The Green dot is a Scottish pub, Fox and the Fiddle, off of king street. Right beside the Fox is an Irish pub called Failte (unofficial pub of the Cpl. For life club of the RHFC)
Those are just some suggestions... all with in walking distance
Cheers,
- Piper