1 and 4 are "impossible" since the game can only spawn 10 notebooks at a time (could be changed but would probably break a lot of things)
2 and 3 are possible to implement, just need to edit some code and they will be good to go.
For the second challenge, do you mean the vending machine AND the notebook finder machine or just the vending machine ?
I would like to hear what item idea you also have if you don't mind