Franklin Gilbert MERRIT RODMAN
Sex: M
Event(s):
Birth: 11 Apr 1848
Fonthill, Welland, Ontario
Parents:
Father: William Hamilthon MERRIT
Mother: Cathering RODMAN
Film #1553592 Batch# 0760035

Other children for William & Catherine show her last names as RODMAN then Pendergast. I dont know what source you have found that makes you believe Franklin Gilbert was son of John and Rachel, maybe you know this for sure. But I wanted to send this LDS birth record I found on a Franklin Gilbert Merritt.
Let me know if you have already verified him as a son of John and Rachel Merritt. I wonder if you have her last name? That might make it easier to find more info.

Note. I did find a few more baptism records for William and Catherine Merritt, one was kind of interesting thought Id pass it on I wish I could find info this easy on Eleanor Emeline Merritt.

BAPTISMS IN NIAGARA, BY REV. ROBERT ADDISON

Baptised at the Ten Mile Creek in 1821
June 3. Jedediah P. Merritt, of William H. and Catherine.
Son of William Hamilton Merritt, and author of the memoirs of his father, the projector of the Welland Canal

Info found at this site.