Yes yes it is all very good but it don't say HOW he became a one of the Nine Divines :shrug:
Naw, man, that summary aligns nearly pitch perfect with Mr. Quimper's assertion that Tiber was mantling Lorkhan. Think of the mystical power of Reenactment.
What did Lorkhan do to solidify the plans for the Mundus? Oh, I dunno, he tricked, promised, betrayed, and made concessions to the various "rulers" of the etada, right? Sounds like the summary, only a few existence lenses down.
And, just like the varying accounts of how that Convention and its consequences have become murky with Time and myth, so too is Tiber's ascension to the first true Emperor of all of Tamriel. Accident? No way.
As above, so below, and that's how you do it. Especially when there's a hole just ready to fill.
Hope that helps.