I'm going to have to disagree here, as I believe these photos show Cooper's Hawk. First of all, the first two photos show a bird with a very full crop, making it look much larger and bulkier.
Goshawks show heavy brown streaking on most of the underside with a buffy backround. Cooper's show fine, dark streaking ending higher on the belly, against a white background. There are certainly exceptions, but I think the photos lean much more towards a Cooper's Hawk appearance.
Cooper's hawk can certainly show the extensive white on the back (e.g
here). While goshawks do have a mottled back, I can't find any photos of goshawks showing the contrasting white patches like this bird.
The eyebrow is certainly an indicator for Goshawk, but Cooper's and Sharp-shinned often show heavy eyebrows as immatures, and in any case the eyebrow, on at least the first two photos, is not particularly strong.
The legs do not look large enough to me to be Goshawk.
I can't comment on what you've heard and seen (i.e. there may well be 1 or more Goshawk present), but I strongly believe these photos show Cooper's Hawk. Goshawk is a very rare bird in the GTA except on migration, and 3 birds in a small park is likely completely unprecedented.
Keep in mind size and bulk can be very misleading for accipiters. Female Cooper's Hawk average about 65% heavier than males.