So, is Fantasy Flight Games going to be putting out an official timeline of events for the new Canon any time soon? Or will GMs have to make due with the old AEG one and have to alter it/randomly place the events and pray they're right?

The most authoritative (and detailed) timeline of events for the new version of L5R is the series of fictions that have been published. You can read them all, in chronological order, at this post in the LCG Lore forum. Why there are two Lore forums--that one, and this one, I'm not sure. That said, if you haven't read the fictions, you should, because they're pretty good (full disclosure...I'm one of the writers )

If you're looking for shorter, less-detailed overview sort of thing, FFG hasn't published that yet and I'm not sure if or when they will. So far, most of what's happened has been set-up and character development, although the story starts to get shaken up at the very end when the Emperor tells the Emerald Champion, Akodo Toturi, that he's going to abdicate, name his YOUNGER son, Daisetsu as his heir (because he doesn't think his older son, Sotorii, would make a good Emperor at all), and name Bayushi Shoju, Champion of the Scorpion Clan, as Imperial Regent until Daisetsu (who's currently 14) comes of age.

Emerald Empire also has a timeline in the first few pages of the book. It's mostly broad strokes, so recent events are best looked for in the Fictions, but it goes from prehistory to the rise of the perfect land sect

I'm taking more for the older histories, details and things I can use for plothooks for the present era: For example: Hantei Satorii being given a fan that is haunted by the Steel Chrysanthemum or what AEG tried to do with the Tomb of Iuchiban as examples.

I'm a little unclear on what you're actually looking for. In your first post, you asked about a timeline of events in the current canon from FFG. In your second one, just above this one, you're alluding to using events from the old AEG lore (I think) to generate plot hooks in the new FFG lore (I think). Happy to offer suggestions, but I just want to make sure I understand what you're asking for suggestions about!

Basically, are you looking for a timeline of events in the newer FFG setting--that is, since the fictions launched with "Her Father's Daughter" (which is actually the second or third fiction chronologically, but was the first actually published); or are you looking for a timeline of events in the old AEG setting covering the same period i.e. the time around the Scorpion Clan Coup and the beginning of the Clan Wars? Or, to distill that even more, are you looking for a timeline for the FFG setting, or the corresponding AEG setting?