Inviting Mother on visit visa, some questions

I am posting to acquire guidance regarding application of my mother’s visit visa to UK. I am living in UK for 7 years and have UK citizenship. I want to invite my mother to UK on a 6 month visit visa. I have attached the following documents with the application:
Documents related to my mother:
1. Visa Application
2. Cover letter
3. Original passport and 2 photographs
4. Previous invalid passport
5. Bank statements up to six months showing transaction history of amounts I sent on monthly basis (approx. Rs. 50,000 / £400 per month)
6. Bank statements of another account showing savings (£15,000)
7. Transfer letter of house to show ties in Pakistan (from housing authority, in English)
8. Assessment letter from architect engineer to provide estimated worth of house (Rs. 1 crore/£60,000)
9. A copy of all original documents and any translations required
Documents related to me:
1. Copy of British passport
2. Bank statements up to six months showing transaction history and savings (last balance £12,000)
3. Six month Salary Slips, approx. £3300 per month take home
4. Copy of tax return
5. A letter from estate agent stating the consent of landlord to let my guest stay in property for 3 months with affirmation by estates agent that property is good enough for the stay of another person
6. Letter of invitation stating
a. Invitation to my mother to visit us
b. Her purpose of visit – She need to spend some time with us (after my recent marriage)
c. Her ties in Pakistan – A house, Some savings
d. Her relatives mainly two children, her siblings and parents. Strongest ties
i. An adult married son and his wife living with our mother in my mother’s property. He own a business but I’m not attaching any documents related to his business
ii. A married daughter, living with her husband and son a few miles away from my mother’s place. She visits her in every two three day.
My Questions:
1. my mother is financially dependent on me for her monthly expenditures and also I am funding her trip including tickets, travel, entertainment and stay. Do the above mentioned documents (property in the form of a house and some savings along with two siblings) assures the visa officer that she would return to Pakistan after her trip to UK? In my letter I have mentioned some ties of my mother. Are these strong enough in support of visa application or do I need to add something for make it acceptable?
2. As my mother is a widow, do I need to provide death certificate of my father as a proof of her marital status? If I don’t attach this document, does it has a negative influence on application?
3. Regarding my mother’s savings in her bank account, does she need to provide any source of those savings if those are in her account for more than six months?

any comments guys??!!!