Well then I don't think I will implement your second challenge idea, however your 3rd challenge has been put in the game and will be in the next update/patch or whatever.
As for your items idea, the bottle of glue is probably the most interesting one and MIGHT be implemented at some point.
For the two other, I don't real want to implement scissors/eraser since I think it's too dangerous to use it on a teacher, as you would most likely either miss it or take damage before using it (unless you want it to work like "An apple for Baldi" in Baldi's Basics, and would be used automatically and take the hit for you).
For the green chemical, I just don't really want player gamble with it, people wouldn't understand how it work too (unless I add poster around the school to explain how it work, which would feel out of place in my opinion)
(Also do you want me to credit you for give me your ideas ?)