Linda, I have several pages of notes on possible relatives of this Alex Brown, but I'm still not sure if or how Tempey relates. I can send these notes to you privately if you want them.
What I can tell you now is that Florence Brown, age 15, in 1851 census was the sister of my husband's ancestor, Mary Brown /Weaver/ Graff. I don't know whether Mary and Florence were sisters to Alex or maybe cousins.
Alex died 15 March 1860 at age 44 and wife Mary McMorris, age 33, died around the same time, both of TB. His first wife, Isobel Burton d. 12 Jan 1856. The children from his first marriage, John, 9, Margaret, 8 and Barbara 7, were placed with Isobel's family. A 6-wk-old unnamed child was placed with the McMorris family.
What can you tell me about Tempey's brother, Alex? This Alex was b. abt. 1817. Does that work? Do you know the names of any other siblings of Tempey? Was there a David? A man of that name seems very close to Alex, witnesses some baptisms, marriages, etc.
One interesting bit: In 1876, Richard Allen (Tempey's son, I think?) married a woman from Glengarry, Ont. Glengarry Co. is where Florence Brown and her husband George Elder settled. Could Richard have met his bride through Florence?