By Alex Nino Gheciu -CP-The initial concept for “Endless Cookie” seemed straightforward: two half-brothers — one Indigenous, one white — tell stories about their different upbringings, brought to life through animation. Making it work, however, proved anything but simple. Seth and Peter Scriver say they began recording sessions for their documentary nine years ago, but things quickly descended into “chaos,” thanks to the lively energy of Peter’s house in Shamattawa, a First Nations reserve in northern Manitoba. “It was impossible to find silence,” recalls Peter on a virtual call from Toronto. “There’s seven kids living in Pete’s house and he’s got 12 dogs,” Seth laughs. “We literally got interrupted one million times. And then it was kind of just like, ‘I think we have to just go with what is…