I ran across a family page (Heartland Grove 9111 slord.htm) listing a Mehitable Ela w/o David McKeen Jr. Mehitable doesn't seem to be listed in D.H. Ela.
I found the family listed in the 1850 Stoneham Census record, and Mehitable is aged 38 so b. abt. 1812 and claimed b. in New Hampshire.
The McKeens had many children including these four who married McAllister siblings: Loren m. Lydia McAllister, Annie P m. Amos McAllister, Silas m. Mehitable McAllister, and Burnham m. Lucy McAllister.

Does anyone recognize this Mehitable?