can you do that on other networks? most of the phone reps say you can't use a smartphone without a dataplan, since "everything goes over data" as they say.. my wife would love a smartphone, but not the dataplan...

You absolutely don't need a data plan - my girlfriend is on Rogers with a smartphone kitted out as a dumbphone. Just turn off packet data (in the network settings menu) and you're set. You might not be eligible for subsidies on some devices though: many carriers have a minimum monthly cost to get the full discount.

Almost always, yes, as long as you own the phone. I had a non-data plan for years with FIDO. If the rep says you can't, ask for someone else.

Wow would love a US equivalent of this if it's out there? Could turn an older iPhone 4 into a cell phone for kid without an expensive data plan (they're without a wireless option about 12 minutes of the day)

I have a AT&T-mvno Straight Talk plan here in the US that costs 45$/month for unlimited data/talk/text - it's vastly cheaper to just purchase the phones outright. Too bad straight talk quit selling AT&T compatible SIM cards a few months ago.