Hello Faaiez,
regarding 1):
The problem in your case was that the (SAP internal) include URLs could not be resolved in your network (outside SAP). Your SAPGUILandscape.xml is set up specifically for SAP internal use.
However, you are right that this should be handled by ADT in a robust way. We are planning to ship a correction in a future release of ADT: Then, includes that cannot be accessed or parsed will be ignored gracefully.
Best regards,
Marco