In chapter 23, what does Jem say the four types of people are and what kinds of people are in Scout's hierarchy?

Jem is trying to map out and make sense the socio-economic classes that make up their rural town of Maycomb, and the surrounding environs of Maycomb County, Alabama. From his thirteen year old point of view, he saw the community divided into 4 groups.

"There's four kinds of folks in the world. There's the ordinary kind, like us and the neighbors, there's the kind like the Cunninghams out in the woods, the kind like the Ewells down at the dump, and the Negroes."

In "white" society there are differences in rank and pecking order. Jem sees caucasians divided by familial lineage, financial, educational and social status, putting the suburban dwellers of Maycomb, like themselves and their neighbors,  at the top of the hierarchy, and the poorer, less educated, but hard working, farmers or laborers like the Cunninghams in the middle of that group. The "white trash" or the most impoverished, uneducated and perhaps most socially backwards group of white folks, such as the Ewells, reside at the bottom of the white society strata.

In the segregated South of that era, the Negroes, regardless of  wealth, education, or career were beneath - and separate- from the Caucasian hierarchy. Racism separated people of color physically, socially, educationally, financially, and in some peoples frame of reference, even morally. People of color were considered totally and wholly separate, and definitely not equals, in Maycomb society.

Jem may have left out the groups that Scout mentions, "the Chinese and Cajuns" partly because they weren't in the vicinity, but also partly because they were regarded as "people of color" and could simply be lumped in with Negroes, because they were not white and therefore not part of the hierarchy of Caucasians.  Aunt Alexandra sees the differentiation in rank and class among white folks as having to with literacy. Those who can read and write are "above" those who are illiterate.

In a strange irony,  young, innocent, clear-eyed Scout actually agrees with her aunt. The difference is she doesn't look down on those who are less educated. Scout sees the difference between white people as really only hinging on one thing - opportunity and access to education. She sees no difference between the Finches and the Cunnighams.

"No, everybody's gotta learn, nobody is born knowin'. That Walter's as smart as he can be, he just gets held back sometimes because he has to stay out and help his daddy. Nothin's wrong with him. Naw, Jem, I think there's just one kind of folks. Folks."

This implies that Scout sees everyone in the white community equally...but differentiates their social status based on their opportunity to access and participate in education. We might surmise that Scout's world view could go further, and that anyone educated and literate would be in the same category, regardless of race, or class.  It's not likely that she saw it this way given racist and segregated society she lived in.