The simple answer to the question of where did the Crow and Bobs Lakes names come from is: no one knows for sure!
Both the provincial and federal offices responsible for place names have no knowledge of the origins of the name, but there is now an official spelling – Bobs Lake, (no apostrophe). The name was approved in 1939 by Geographic Board of Canada, which appears to have often simplified names by dropping an apostrophe where one existed before.
For Crow Lake:
As with Bobs, there is no known origin of the name. Local author, Lloyd Jones (author of The Dammed Lakes, An Environmental History of Crow and Bobs Lakes published in 2003) thought he knew the origins:
Every morning when I am wakened at dawn by crows speaking to each other from the high hills surrounding the lake, I am reminded of my nomination for the origins of the lake’s name – the early loggers on the lake may have been wakened the same way.
LLoyd B. Jones
The origin of the name Crow Lake is apparently not recorded anywhere either; consequently, only speculation is possible.
Samuel Benson named the lake “Clear Lake” on his 1824 survey map, so obviously his naming did not stick. The stream flowing from Crow Lake to Crow Bay was known as Crow Lake Mills about 1840; European loggers, already active on the lake, could have named it.
A Mississauga settler, Peter Crowe who lived at Devil Lake, has been proposed as a possible source of the name, but whether he had any connection with Crow Lake is not known.
In 1826, Oso Township’s first surveyor, Publius Elmore, did not name any lakes there. He did not record any human activity, so there was no one even to suggest a name to him, and he apparently did not know about Benson’s Clear Lake label either. Elmore, then, was not the source.