A list of the progress of the Lore Update, as of 2017
At this time, all characters have had their bio updated to match the current lore. Good job Rito [slayer-jinx-wink]
Missing Longer Bio and Short Story

Only Missing Longer Bio:

Received both Long Bio and Short Story:

As it stands, we are about 50% complete with the lore conversion process in terms of champions which began with the Burning Tides Update in 2015. The last location to receive a lore update was partially Ionia in April, 2017. This leaves the following areas left to update.
The other half of Ionia, the Freljord, Noxus, Bandle City, Kumungu, Icatha/The Void. We can probably assume the other half of Ionia is next. I'm taking a wild guess and saying Noxus is after. We probably will see the removal of Kumungu as a location however, due to both Rammus and Wukong being moved from there, cutting their champion representation in half.
With regards to the champion update schedule, I think these are the most likely to receive bio updates soon:
(I think Udyr will be moved back to Ionia) 
By current estimates, I expect the process to be complete around mid 2020, assuming a similar pace. In six months, I will make another thread to see how far we have come since this one.