I tried to find records that would show more information about the parents of George Pearce -- and it doesn't help that the death record gives his birth date as Sept 1832, when everything else (census records) put his birth date as early as 1825. The death record looked like some information was scratched out and changed later, so it's hard to know how much faith to place in the information there. (Here's the link to make it easier for others to find if they want to tackle this: https://familysearch.org/ark:/61903/1:1:F8ZT-N7Z )
I didn't find what you are looking for about George's parents (apart from the indication that both were born in Rhode Island), but I did find some census records you might not have located, since they had mistakes in the way they were transcribed: They only show George and his family, though, and not his parents (except for his wife's parents).
Here is 1850: (The Disley family is next to George and Mary's household, so I'm pretty sure this is the right family.) Mary's initial is written as an "F".
"United States Census, 1850," database with images, FamilySearch (https://familysearch.org/ark:/61903/3:1:S3HT-DZ23-CF3?cc=1401638&wc=95RS-FMX%3A1031317501%2C1031572701%2C1031677701 : 9 April 2016), Rhode Island > Providence > Providence, ward 1 > image 166 of 172; citing NARA microfilm publication M432 (Washington, D.C.: National Archives and Records Administration, n.d.).
George Pierce 1850 Male 25 White 1825 Rhode Island 963
Mary F Pierce 1850 Female 23 White 1827 Rhode Island 963
William Pierce 1850 Male 1 White 1849 Rhode Island 963
Susan Pierce 1850 Female 7 White 1843 Rhode Island 963
Elizabeth Pierce 1850 Female 4 White 1846 Rhode Island 963
George Pierce 1850 Male 2 White 1848 Rhode Island 963
*I'm curious about how the children are not in chronological order. Maybe the 1 year old is the only biological child and the others may be relatives, but not their own?? (Total speculation).
You probably have this one-- the 1860 US census
1870: This one had some mistakes, but if you look at the whole family, I think it looks likely that it contains the same individuals.: https://familysearch.org/ark:/61903/3:1:S3HT-69B7-QJF?cc=1438024&wc=92K3-822%3A518652501%2C518798901%2C518978201
There were several other census records that were more recent, but you probably have located them.
Wish I could have found something really helpful.