Just my thoughts on example #2
When I look at the soil surface--its clean and appears dry. If you're hoeing this to keep it clean--be careful; you will easily damage the stem roots just beneath the surface which are needed to feed the plant. And if you're not hoeing, then why don't I see any sign at all of even a weed or a blade of grass. Usually when I see that I think low organic matter or soil chemistry problem because weeds are a good indicater of soil health. (If you overfertilize early and allow to dry out then that could also cause this) And I see no mulch of any kind; it appears that bare soil is exposed to hot sun allowing the soil temperature to go too high and dry out. Stem roots like it cool and evenly moist. What I would do now is add a inch or two of well rotted cow manure or composted cow manure, water in and the mulch about 2 inches deep. After blooming feed with a well balanced FORTIFIED fertilizer ( with micro nutrients) How you treat these bulbs this year has a lot to do with their stamina and resistance to desease/blights next year.
Which leads to your example #1. One must think back on 'what was, or what wasn't' done way back up the road--last year; even the year before that. Healthy plants are resistant plants--even to blights to a good extent. This is not typical black spot botrytis, tho there are several types. This most likely cause is a soil chemical imbalance that is responsible for this condition.
Daconil is good for contolling fungi and molds and I use it on my peach trees for leaf curl. However, its not my favorite when it comes to lilies. I much prefer a copper base fungicide.
