1. Yes. If both instances are active on node one and passive on node 2, right-click on one of the two SQL Server groups in Cluster Administrator and choose Move Group. Make sure you understand the licensing implications of making this change.
2. You can see this in Cluster Administrator, of course. If you need to know this from T-SQL, you can SELECT SERVERPROPERTY('ComputerNamePhysicalNetBIOS') from each instance. If they are the same, the cluster is active/passive and the name returned is the active node. If they differ, the cluster is active/active.