It does not permit relicensing. You may use it in an aggregate work with other pieces that have a different license, including proprietary or GPL, but that does not mean your code is relicensed.
2. As the code is not relicensed you have to follow the terms. Generally for example even BSD licensed code (other than BSD0) requires that you include attribution both in source code and binaries or documentation, so you need to keep a full list of licenses and authors and list them out in the docs.