Doesn't seem like it will take much warming for them to be viable in the GTA though, if they are native to SW Ontario.
Kentucky Coffee Tree is viable in Toronto now; I would argue it's showing some signs of being invasive (I've seen it colonizing in a couple of spots in the ravines.)
My concern first is mislabeling. Let's simply be accurate. There are 100% authoritative lists of what is native to Toronto published by the TRCA. Don't call it 'native' unless it is native (to Toronto)
Second, when introducing species which aren't native, one gets into the realm of unpredictable effects. Should the species do well here, it may displace trees that are native; that may in turn effect local birds, insects, and other wildlife.
Ginkos do quite well in Toronto (and aren't native to North America at all); they also, though, aren't invasive.
However, they notoriously feed and host virtually nothing. Which means some landscape architects love them, because they're highly pest resistant.
But on the other hand, not good for the local eco system. Fine to put one here or there, not great to be planting thousands.