I can't imagine how a Canyon Inflite would come close to fitting him.

My kid is about the same height and she is riding a 49 inch 700c cross bike that's a tad big on her and a XS Giant Liv road frame, 700c. Do you have a junior program in the area? I would see if anyone is selling a used bike and save yourself some money as the kiddo will grow out of it pretty quick. The resale value buying used is much better than buying new. Canyon does have a fit guide where you can plug those numbers in and it will spit out a frame size. I wouldn't be surprised if their very smallest frame does the trick. . . but that's a lot of money for a bike the kid will grow out of in a season or two. And don't worry about the weight, it's going to be suck no matter what with how small the kids are. I feel so bad for those kids in the muddy races, sometimes the bike weights more than them.