First, thank you all for helping out.

Let's answer two quick questions first:

1. Romanians still need a Visas to come in the US.
2. Form I-551 is the official name for the green card, therefore she DOES have this. (She also has the expired visa she initially came with).

And CkCrunch, thank you for the very detailed response, it helped a lot, but there is one more thing i do not have an answer to:

When she gets to Germany, she WILL need to go through customs from what she's telling me. How would they do the checks over there in Munich?

Thanks again!