Michael,
I had some time so I thought I would try to look for your ancestors again, and this time I had some success...

1930 Census
SD, Shannon, Township 38, ED 28, p. 55 B, 25 Apr 1930
dwelling 39, family 41

Plenty Wolf John, head, has radio, male, Indian, age 44, married at age 18, reads, writes, born South Dakota, full blood, Oglala Sioux, speaks English, farmer, tenant farm

Plenty Wolf Louisa, wife, female, Indian, age 45, married at age 19, reads, writes, born South Dakota, full blood, Oglala Sioux, speaks English, no occupation

Plenty Wolf Victoria, daughter, female, Indian, age 16, attends school, reads, writes, born South Dakota, full blood, Oglala Sioux, speaks English, no occupation


Plenty Wolf Kiva, daughter, female, Indian, age 14, single, attends school, reads, writes, born South Dakota, full blood, Oglala Sioux, speaks English, no occupation

Plenty Wolf Alvina, daughter, female, Indian, age 12, single, attends school, reads, writes, born South Dakota, full blood, Oglala Sioux, speaks English, no occupation

Plenty Wolf Mattie, daughter, female, Indian, age 9, single, attends school, reads, writes, born South Dakota, full blood, Oglala Sioux, speaks English, no occupation

Plenty Wolf Selven, son, male, Indian, age 4, single, born South Dakota, full blood, Oglala Sioux, no occupation

Plenty Wolf Benard, son, male, Indian, age 9/12, single, born South Dakota, full blood, Oglala Sioux, no occupation

I also found this in the social security death index:
JOHN PLENTYWOLF, born 20 Dec 1885, died May 1970, last residence 69347 (Hay Springs, Sheridan, NE), last benefit (none specified), ss# 503-64-2716, issued South Dakota

In the 1900 census is Charles (born 1852) and Emma (born 1863) Wolf Plenty (probably a census taker error- there are NO Plenty Wolfs) with children John (born 1887), Emma, Samuel and Alice. They are on the Pine Ridge Res.

In the 1920 census, the only Plenty Wolfs I have been able to find so far are:
George (age 22) and Samuel (age 24) listed as step-sons, with the parents being Elk Eagle (age 62) and Emma Eagle (age 61).

I haven't been able to find them in 1910 yet...

I will keep checking as I have time, and see what else I can find for you.
Susan