We do not have an evidence that Zulaikha or her husband were Mushriks. Many scholars say that if the Azeez (King) of Egypt was a Mushrik, he would have never behaved with Yousuf in the way he behaved and he would have never given him the charge in the treasury of Egypt. Zulaikha tried to do wrong against Yousuf but she could not because of the firm faith and strong will power if Yousuf. Later in she has repented and become a good person. Allah (SWT) forgives every sincere person who repents and seeks forgiveness.