The word "them" refers to Cornelius and his Gentile guests and household. Peter does not call them Gentiles in his account to the Jewish believers at Jerusalem.
The word "they" refers to the Jewish believers to whom Peter spoke. The word "us" includes all of the Jewish believers. (See: [[rc://en/ta/man/translate/figs-inclusive]])
Peter uses this question to emphasize that he was only obeying God. AT: "Since God gave to them ... I decided that I could not oppose God!" (See: [[rc://en/ta/man/translate/figs-rquestion]])
"God has given repentance that leads to life to the Gentiles also." Here "life" refers to eternal life. The abstract nouns "repentance" and "life" can be translated as the verbs "repent" and "live." AT: "God has allowed the Gentiles also to repent and live eternally" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])