Answer
Wa `alaykum as-Salamu wa Rahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
Your wife can do all what pilgrims do except for Tawaf and Sa`i.
Responding to your question, Dr. Muhammad Salama, PhD, Islamic Studies in English, Associate Professor at the Faculty of Islamic Sciences al-Madinah International University (Mediu), states:
Your wife has to make the intention of ihram before passing the miqat and her ihram is valid even if she has her menses.
When you arrive in Makkah, she may perform all the rituals with the exception of Tawaf and Sa`i as she has to wait until she becomes clean to perform them.
Aishah (may Allah be pleased with her) reported, “I had my menses when I reached Makkah. So, I neither performed Tawaf, nor the Sa`i between As-Safa and Al-Marwa. Then I informed Allah’s Messenger (peace be upon him) about that and he replied, “Perform all the rituals of Hajj just like other pilgrims, but do not perform Tawaf around the Kabah till you get clean (from your menses).” (Al-Bukhari and Muslim)
Allah Almighty knows best.