Whoops! It seems that there is a resolution; well, partially.
Asa Tapley, in the 1852 census, would appear as I suspect a s/o Alexander Tapley. The Samuel he is with is, as it would seem, not his brother; but a nephew and a s/o Nathaniel Tapley. For this younger Samuel (who would seem to be Mary Ann (Tapley) Springstead's brother) I have notes:
2. SAMUEL TAPLEY b. ca. 1797, d. 19JAN1870 age 72 years, bur. Tapley Cemetery, Brantford Twp., Brant Co., ONT, m. 1st Prince William York Co., NB 1JAN1817 MARY A. _____ (b. ca. 1805, d. 26SEP1841 age 36 years, bur. Tapley Cemetery, Brantford Twp., Brant Co., ONT); m. 2nd MARY HUBBLE (b. ca. 1817, d. 7JAN1886 age 68 years, bur. Mount Vernon United Church Cemetery, Brantford Twp., Brant Co., ONT; m. 1st Asa Tapley.) (See Asa Tapley, below.)
In their marriage bond, dated York Co., NB 1816, Mary is given as Mary A. Tapley. The only way it could have been is if Mary was Samuel’s first cousin, and a daughter of Samuel, s/o Alexander; at least in York Co. at that time. The co-signer of the bond was James Foreman (a Foreman m. a Tapley in York Co., NB); and all were of York Co. Obviously, this bond was issued for the marriage which took place 1JAN1817. They were of Prince William, and Nathaniel Tapley and Charlotte Drake were witnesses. It is possible that Samuel and Mary had entered into either an informal marriage (i.e., declaration before family and friends), or a form of marriage not officially recognized (i.e., one performed in a Congregational Church.) My understanding is that the only marriages recognized as valid in NB at the time were those performed by Anglican, Presbyterian or Roman Catholic Churches; or by Justices-of-the-Peace. So, when ‘officially’ married, in 1817, Mary (having been Samuel’s wife for at least four years), would sign herself as Mary A. Tapley.
Note that I go to great lengths to establish that Samuel's first wife was not a Tapley; BUT what if I am wrong. What if I am correct in assuming that, if a Tapley, she was Samuel's 1st cousin? What is she was Asa's daughter (not wife as suggested by a vague tradition?) Asael Tapley and Mary Drake m. (as it turns out) in 1800. The earliest child known was Osmond (1813), but surely there must have been earlier children. These conclusions are not established, but they make a sort of sense of what is available so far. Asa/Asael and his wife separated; he went to Upper Canada to live with his eldest daughter, she died but he lived on with his son-in-law who just happened to be his nephew.