The order of events predicted by the WT and repeated somewhat above is different from what Rev 16 foretells.
In Rev chap. 16 the order is:
v.16 And they gathered them (the kings of the earth) to the place called Armageddon
v.17 The seventh bowl of God's anger is poured out. Resulting in:
Divine pronouncement that "it is finished" or "come to pass."
v.18a 'Lightnings, voices, and thunders' occur
v.18b An unprecedented 'great earthquake' occurs. Resulting in:
v.19a The great city being 'split' or 'becoming' into three parts
v.19b Cities of the nations fall
v.19c Babylon the Great is given God's cup of anger
v.20 Islands and mountains removed
v.21 Unusually great plague of hail affecting people
There is a lot of symbolic language. But what I'm highlighting is the order. "Armageddon does not "occur." Armageddon is a "place" that the kings of the earth are "gathered" to. And all the events listed afterwards 'occur' after the kings are gathered to Armageddon.
The regular use of "and"/ "also" (Greek kai; Rev 16:16-21) before every event is a rhetorical device called polysyndeton. It indicates the events listed, happen in the order listed or sequentially. Thus, the entire "earthquake" happens after the kings are 'gathered to Armageddon.'
The 'great city' of v.19a is, by reason of the listed order, a different entity from 'Babylon the Great' of 19c. What John has explained to him in 17:16, 17 is with reference to v.19c. (see 17:1) So that the 'ten horns' and 'scarlot beast' 'hating of the harlot' is describing an event that takes place after the symbolic gathering to Armageddon, after the earthquake commences, after the great city is split into three parts, and after the cities of the nations fall.
Also, if you read 17:16, 17 carefully, you will see that both the ten horns and the scarlot beast hate the harlot. But God only puts something into the hearts of the ten horns. And the result of his putting something into them is 'their giving their power and authority to the scarlot beast until God's words are accomplished.' So, what God puts into the hearts of the ten horns cannot be hatred for the harlot. Otherwise, there is no explanation for why the scarlot beast also hates her.
The great city of 19a is in reference to the great city of 11:8. (There are two 'great cities' in Reelation - 11:8 & 17:15) Up to the end of chapter 16, Babylon the Great has not yet been called 'the great city.' The 'splitting into three' of the 'great city' is an allusion to Ezekiel chapter 5. Both Ezekiel 5 and Rev 11:8 are references to Jerusalem or whatever Jerusalem might symbolize in Rev 11:8. (Ezekiel 5 was about literal Jerusalem and its being attacked by Babylon, although Babylon is not mentioned in the chapter.