Let's see if there are meaningful associations with Ma's name as there was for Pa's:
Carolina = a version of the name Caroline, a name associated with royalty
Hmm. Not sure there is much of the royal about her other than her dicatitorialness.
Carper = a person who habitually carps, who talks too much and regularly finds fault
Now that seems to fit.
carp = an ornamental freshwater common koi. Several species of carp are listed as invasive species by the U.S
Izaak Walton said about carp in The Compleat Angler, "The Carp is the queen of rivers; a stately, a good, and a very subtil fish; that was not at first bred, nor hath been long in England, but is now naturalised."