Please check whether the Dot Net platform is installed in your system. Run the utility available in the bin directory, DotNetUtilities.exe , it will tell you the Dot Net version. If Dot Net platform is not available in the system, download the platform. Please see the software requirements page for downloading the platform.
Yes, you can view more than one mode of data retrieval at any given instance. If you click "historical data", historical data will be active in the main window. Again, if you select "Live feed data" it will start live feed polling.
Yes, you can monitor more than one instance using EC2 Health Monitor Tool. If you select a instance in the tree, tool will populate the performance metrics for that instance. Any instance can be selected for monitoring.