Torah Temimah cites Keritot.
“For his shogeg” — only one whose chatas and shogeg are of the same type; this excludes the anointed kohen (whose liability structure differs).
Miyut of matching shogeg/chatas profile — excludes the anointed kohen and the community.
Kohen Gadol and Sanhedrin do not bring asham talui; their liability structure differs. The Torah’s language “al shigegato” is limited to the ordinary individual whose chatas and shogeg match.