Executives orders are only good for as long as the president is in power.
Not true, presidents are famous for signing last minute executive orders (EO) just before the end of their administration.
The Supreme Court can overturn EO’s, and has done so, but only twice.
The next president can issue a new EO, which can change things, but EO’s tend to be sticky.
Here’s an example from the end of the Bush administration: http://media.www.vanderbiltorbis.com/media/storage/paper983/news/2009/01/21/Newsfeatures/Bush-Signs.LastMinute.Executive.Orders-3588927.shtml
The most famous EO? The Emancipation Proclamation (which was actually 2 separate EO’s)
The first EO? - 1789, by the President Washington.
No, they are enforceable until the Supreme Court says they aren't enforceable, or until Congress passes legislation reversing it, or until a subsequent President writes a countervailing or amending order.