I think the second one could be done by this trigger, using a dummy item with one charge (better having variables, but at first an easy solution)
Events
Unit - A unit Uses an item
Conditions
(Item-type of (Item being manipulated)) Equal to [Dummy Item]
Actions
Visibility - Create an initially Enabled visibility modifier for (Owner of (Hero manipulating item)) emitting Visibility across (Playable map area)
Wait 5.00 seconds
Visibility - Disable (Last created visibility modifier)
Didn't test it, perhaps you have to add this trigger after visibility modifier creation:
Visibility - Enable (Last created visibility modifier)