I was pondering Zephaniah again. Your outline shows all nations worship of God per 3:8-13. I do not see that concept portrayed. The closest is the reach of the diaspora even to the dispersed ones of Cush.Outline of Tz'fanyah (Zephaniah)
1. Judgment Day
A. Judgment upon the earth 1:1-3
B. Judgment of nations 1:4-3:7
2. Day of Hope
A. All nations will worship God. 3:8-13
B. God reigns. 3:14-20
Shalom
For everyone, here is the BibleProject interpretation of Zephaniah. It comes some close in the first 2 chapters to what I have mentioned. It veers some in chapter 3 though.