Your information is valid for the note. The left signature was applied, probably at the branch level, in pen and ink. The engraved right signature is that of Sir William McMaster, after whom the university is named, and the founder of the bank. Nineteen surviving examples of the note have been recorded; yours will make twenty. Current catalogue value is $750 for Good condition, $1,400 for Very Good; $2,250 for Fine and $3,000 for Very Fine (the finest known, and it is in an institutional collection.) I suspect current market values could be a bit higher. The note was printed by British American Bank Note Co., which is still in business and producing most of our current spending money, although under new ownership.
The $4 denomination was used by most banks; it was the equivalent of the old Canadian pound currency (known as Halifax currency and not to be confused with sterling). Although decimal currency was adopted in 1857 or so, some of the older folk kept their accounts in pounds and shillings long after, and the $4 denomination was not withdrawn until 1912. Banks lost the right to issue $4's in the bank act revision of the early 1880's and the Dominion Department of Finance took over, with issues dated 1882, 1900 and 1902.
The vignette at the left is called "The first lesson", showing a grandmother teaching a girl to knit, as you said.
I'm not sure what kind of information you are asking for - if I've missed it, just ask.
Can you share a scan with us?