When we adopted our kittens they were also on Wellness tins. They are now on a 80-90% raw with 10% Wellness diet.
There's nothing wrong with beef as long as your cat isn't allergic to it - both my kittens are currently having ground beef daily along with chicken necks, hearts and liver.
I don't know if Manitoba has a T&T supermarket (Asian supermarket) but your best place to try for organs is an Asian butchery .
Independent butchers are also a great place for carcasses, if they cut their own chicken breast meat, they'll usually have lots of carcasses for sale - I know mine does and it's really cheap like .99cents a pound. Speak to your butcher about keeping meats and bones for you! they're usually happy to do it.