The April 25 1930 edition of the Toronto Daily Star included these three renderings of new upscale houses in the Forest Hill district:

When looking these houses up in Google Street View, I discovered that 112 Old Forest Hill Road and 128 Forest Hill Road are still standing.
The house on Ava Crescent was actually at 7 Ava, not 10. The 2009 Google Street View photo clearly shows this house; by 2019, it had been torn down and a new larger house put up.
The Toronto city directories might have inadvertently caused this problem. The 1931 directory lists Alfred A. Walker at 10 Ava Crescent, not 7. The 1932 directory is confusing: it lists Alfred A. Walker at 10 Ava and Alfred E. Walker at 7 Ava. The Names section of the directory lists Alfred A. as the president of the Hudson-Essex company at 10 Ava, and lists Alfred E. at 7 Ava with no listed occupation. By the 1933 directory, Alfred A. is listed at 7 Ava. He is there in 1937 as well.
Either the city directory didn’t have the address correct, or Mr. Walker was living at 10 Ava for a bit before finally settling in at 7 Ava. I’m not sure.