Will say in the policy details but i'd say no. Pretty sure they cover for stuff like missing flight due to car breakdown on way to airport so I suppose you could blag it a bit?.
I don't understand the question...standard travel insurance will cover the travel you have booked regardless of who it is booked with subject to the conditions of the policy.
No policy is going to cover you if you just decide not to travel though, you must meet the policy conditions.