Is it permissible to pray the 'Isha, then its Sunnah, then the Shaf' (even-numbered rak'ahs), and then the Qiyam (night prayer) followed by the Witr?

The two rak'ahs of the regular Sunnah prayer for Isha are ratibah (supererogatory and consistent) and are prayed immediately after Isha. It is permissible to delay them until midnight. As for Shaf', it is Sunnah to perform it with Witr without separation, except by a salam (salutation of peace), though separation between them is permissible. The Malikis held the view that it is permissible to pray the two rak'ahs of Shaf' after Isha, and then the one rak'ah of Witr after some time, even if the separation is long, based on the intention for Shaf'. Whoever does not stipulate a specific intention for Shaf' should pray two more rak'ahs to complete Shaf' and then pray Witr. It is legislated to perform Shaf' with Isha and delay Witr until the end of the night, especially for those who pray Witr after Tahajjud.