In terms of Toronto vs. Montreal, are any of you more familiar than the other,
The only thing I know about Toronto is the coach bus stop, and having walked up/down Bay street and across Yonge (?) street 8 years ago. I wouldn’t mind (re)discovering it, but I’d certainly be a tourist, unable to advise on entertainment possibilities there.
Montreal, on the other hand, is my home turf, so I know it reasonably well.
local enough that you could help us with tips and advice on booking meals and evening activities
Any large city will have no shortage of restaurants, but Montréal is kind of notorious for this in particular. Wikitravel bombastically says:
Montreal is a culinary mecca, with more restaurants and cafes per square kilometre than anywhere in the Americas. The city has a massive variety of food options, from diners and fast food to haute cuisine to the incredible vegan diversity across a plethora of cuisines from Chinese to Ethiopian to Italian to Afghan to Peruvian to authentically Quebecois. The city was recently ranked 2nd best dining city in North America after San Francisco and ahead of New York […]
Montreal’s “Plateau” neighborhood in particular (and to an extent the old port, downtown, etc.) is everything you want within walking (and walkable) distance. We also have streets that get completely converted to pedestrian-only streets with restaurant patios in the summer.
Now, that’s for individuals / smallish groups.
Montréal has a dizzying array of festivals (especially in the summer months) and urban activities. It also has big natural and urban parks (if you folks are into picnic and whatnot). I even have a big triple beach volley ball court (with real sand and all that), if you want to get some sort of volleyball tournament going. I also know some local tour guides.
If what you want is me (or Regento’s team) organizing “turn-key” events in dedicated venues (outside the main hotel venue) where we’d cater for 250+ people with food, drinks and DJ, I could get that done, but of course that’s another ballgame and that’ll depend on your sponsorship budget for food & entertainment costs, if Flock is going to be footing the bill for attendees. I can book an entire cultural arts center, exposition hall (or litterally the international Expo venues in the beautiful park on its own island, but again: budget & logistics), or a whole nightclub (or restaurant, microbrewery, theater, or other event spaces in modern or historic buildings) if you need me to, it really depends how tame or wild you want to go.
any idea in the price factor between the two cities with hotels and things to do?
There’s easily over two hundred hotels in Montréal, so until we work out the budgets, attendance, logistics and requirements, it is impossible for me to give you an exact price, too many variables involved (including the neighborhood, dates, amenities, etc.)… so in terms of “price factor” estimation, I’d bet it would be less expensive than Boston, and “overall similar to or less expensive than Toronto” 
As for the price for non-hotel everyday things, well it’s pretty much always going to be a bit less expensive than Toronto. See also: