John Gill Commentary Ezra 8:24

"Then I set apart twelve of the chiefs of the priests, even Sherebiah, Hashabiah, and ten of their brethren with them," — Ezra 8:24 (ASV)

Then I separated twelve of the chief of the priests
That were in company with him; so that it seems there were more than the two mentioned, (Ezra 8:2) , very probably their families, or some of their brethren, were with them:

Sherebiah, Hashabiah, and ten of their brethren with them ;
these men named were Levites, and not priests, (Ezra 8:18Ezra 8:19) and therefore the copulative "and" must be supplied:

and Sherebiah
or with the twelve priests, Sherebiah, &c. and ten Levites more with them; so that the number of priests and Levites were equal, and in all twenty four.