Selina was married in Saint Mary parish yes?

There is no family in St. Mary that matches in 1880 census, but there is a family that could be yours next door in Terrebonne:

1880 Census Place: 10th Ward, Terrebonne, Louisiana

Source: FHL Film 1254473 National Archives Film T9-0473 Page 375C

Relation Sex Marr Race Age Birthplace
S. MOORE Self F W B 50 LA.

Occ: Works On Plantation Fa: --- Mo: ---
E. MOORE Dau F M B 23 LA.

Occ: Keeps House Fa: --- Mo: LA.
H. MOORE Son M S B 15 LA.

Occ: Does Nothing Fa: --- Mo: LA.
M. MOORE Dau F S B 12 LA.

Occ: At Home Fa: --- Mo: LA.
A. MOORE Son M S B 8 LA.

Fa: --- Mo: LA.
M. MOORE Son M S B 7 LA.

Fa: --- Mo: LA.
D. MOORE Son M S B 5 LA.

Fa: --- Mo: LA.
S. MOORE Dau F S B 3 LA.

Fa: --- Mo: LA.

There is a Sylvestre Moore in one other place in 1880 census LA but seems to be too old, wife Elizabeth and no children in the household.

1880 Census Place: St. Charles, Louisiana

Source: FHL Film 1254468 National Archives Film T9-0468 Page 368B

Relation Sex Marr Race Age Birthplace
Sylvestre MOORE Self M M B 55 LA

Occ: Laborer Fa: VA Mo: VA
Elizabeth MOORE Wife F M B 43 NC

Fa: SC Mo: NC