My US-citizen partner has been working in Germany for the last 3 years. She has been working in an intragovernmental organization and as such did not receive a 'proper' German visa but instead was issued a Sonderausweis. Since a few weeks ago, she no longer works at this organization (and she had to turn in her Sonderausweis as a result) but instead is expected to start working at a regular German employer (she's a scientist and will work at a scientific institute). Her contract is in the process of being set up and she will sign it within a few days. Once she has the contract she will apply for a Blue Card, which she is expected to get, but it will take 4-8 weeks. Right now she has no visa for Germany or the Schengen area.
We planned a trip to the US at the beginning of October and we are starting to get worried about re-entry into Germany. Most probably the Blue Card application will not have gone through by then. Will this be an issue? Can she simply re-enter Germany without a visa under the rule that Americans are allowed to stay in the Schengen area for 3 months? Is there something we need/can do to make re-entry possible? Does bringing proof of residency/work contract make any sense?