Q1 has allready been answered by TheMeinTeam:
All Coalition members join the war unless they can't. (Truce on offensive wars, other wars) not sure about loans and regencies,
Q2: only cores and claims applies only to the one who are in a coalition against the enemy. as long as you are not in a coalition you are allowed to take what you can.
All Coalition members join the war unless they can't. (Truce on offensive wars, other wars) not sure about loans and regencies,
Q2: only cores and claims applies only to the one who are in a coalition against the enemy. as long as you are not in a coalition you are allowed to take what you can.