Lantern Spires do not drop wispies at all. Collected from 13 Spires and didn't get any wispie. Then collected from 10 Watchtowers and got 3 wispies.
Now waiting for the information regarding the timer of the main prize. If the energy drops are going to be so low and timer is 22h, I am done with this event and start collecting energy. Still need a lot of drops from dead trees, and my drop rate from them was very low. Thank you, pocopicasso, for informing about the drops. It would have been very disappointing, to realize all that in the end of the event. Now at least there is some more time for saving the energy. I have almost all ingredients except Ivy's wispies for constructing the cloud. Now I just wait for Ivy and will try to place the empty cloud as I like the empty one's appearance.
Good luck to everyone who decided to continue the event. Though the poor wispies drops (and as a result huge energy demand) and prizes, I like the fact that no game babysitting was required this time.