In short, no. The Metro does not come very close to the M&T stadium. The lightrail does, however, come much closer.
http://www.mtamaryland.com
The Convention center stop it right on the gate of Camden yards. M&T isn't much further to the west and south a little. BTW, I have NEVER EVER seen someone actually get ticketed on the Lightrail, so save your money if you're willing to be brave.
Yes. You can take the metro to Orioles stadium.
There is no metro line that runs from Baltimore Airport to Washington DC as of October 20, 2013. You must take a car between these two cities and hubs.
two to three working days
probably 5 days
5 working days. If you pay it in after 6pm it counts as the next working day
why does my GEO metro have no take off power
Take the MARC train. It is around $6-7. There is a short shuttle from the airport to the amtrak station. You will arrive in downtown DC at Union Station where you can take the METRO.
Baltimore is in Maryland
no
yes
30 minutes by metro
yes