Will wudhu which a Ma'zoor woman made for Tahajjud Salaat suffice for Fajr Salaat?

Answer

Yes, with Tahajjud's wudhu she may perform Fajr Salaat.

Correction:

This answer is incorrect. The Wudhu of a Ma'zoor terminates with the expiry of a Salaat time. The entire night until Subh Saadiq is the time of Isha'. Isha' Salaat time expires with Subh Saadiq, hence the Ma'zoor's wudhu will end with Subh Saadiq. For Fajr Salaat, the Ma'zoor has to renew wudhu. On the other hand, if the Ma'zoor makes wudhu after sunrise, then such wudhu will be valid until the end of Zuhr time. The entry of Zuhr time will not invalidate the wudhu which the Ma'zoor took after sunrise.