Unfortunately, I don't know the location of the original that the typescript was based on, or how to determine if the "e" ending of Livingstone was added by the typist. I suspect it was typed up by a Purdon relation in Brandon, Manitoba in the late 1940s or 1950s. We have similar-looking typed copies of the wills of Isabella Gillespie Purdon and her husband Robert Purdon, and they both died in the 1940s. (Robert Purdon, d. 1946, was a grandson of Alexander Livingston whose will is under discussion). I have noticed that several descendents born from circa 1890 and through the 20th century have middle names "Livingstone", so a shift in usage could have influenced the typist.
I assume witness John Livingston was Alexander's brother (b. about 1792), married to Catherine Sinclair, and still residing in Lanark County in the 1861 census. There were 9 children in this family, but I have not traced their descendents. (I have no proof they were brothers.) Other witnesses were relations: Donald McKellar was married to his wife's aunt, Duncan Stewart was Alexander's brother-in-law. Jean Livingston (also believed to be a sister of Alexander) was married to a Neil McNiel (also of Mull), so the witness Donald McNiel may also be a relation. The John Currie mentioned was almost certainly the brother of Alexander's wife, Mary.
Unrelated to the will questions you raised -- but relevant to this thread: I've been unable to trace Alexander's widow (Mary Currie Livingston) or his son Duncan (b. about 1831) (and wife Effie/Euphemia) beyond the 1861 census. I believe the index to the 1871 census entry for a Duncan who died in the year preceding the census is for *this* Duncan, and that death was recorded in the Hibbert Twsp., Perth County census. He didn't necessarily die there, but this is where Duncan's sisters Barbara Purdon and Christina McKellar lived -- and Duncan's sons Alex and John appear to have been split up and are each in one aunt's household. I have to assume that Duncan and his wife and mother all died by 1871. Alex (born 1861) and John (born 1863) are difficult to trace beyond 1871 as well, so perhaps descendents of their will find this forum!