I was pleased to see Lawrence on his death cert.I wouldn't feel comfortable following a name that can't be found unless a document also provided that name.Now, death cert info was reported by someone other than him ... if his wife was alive, a relatively good source; if the info provided, fell onto children and no sibling named Lawrence, I'd keep an open mind as to the name not being accurate -- or a middle name.
Next, the name Lawrence is not particularly common.And, assuming there were more sons to the O'C/Pren marriage, 90% of them would have named a first or at least a second born son Lawrence ... we should at least be seeing come Lawrence O'C's around in Kerry.
Take reported dates of birth with HUGE grains of salt.Anywhere near 5+/- years (tho I have a 9-yr consistent error in my own Irish family) and open minded with baptismals dates too (sometime you'll find they baptised them on Saint's Days near the bdays).
Could Prendiville have died in childbirth, yes.So I'd be looking to match YOUR John's children's name to some of these O'Cs at Kerry records:
Area - KERRY (RC) , Parish/Church/Congregation - CASTLEISLAND Baptism of JULIANA CONNELL of GLAUNLARHAN on 10 March 1828 Date of Birth 10 March 1828 (BASED ON OTHER DATE INFORMATION) Address GLAUNLARHAN Father LAURENCE CONNELL Mother ELLEN SWEENY