MIL Visit Visa

Hello All,

I am in the process of applying for a 6 month visit visa for my mother in law to visit from India.

I am sponsoring her application as I am a British citizen, my wife is here on a spouse visa and has recently given birth to our child (we want our MIL to come visit her grandchild).

I work and my wife is unemployed/housewife.

I have the following documents:

my Employment letter from work (stating salary, job title etc)
my Tenancy Agreement
my Passport
6 month Bank statements from myself
sponsorship cover letter
Wife's passport
MIL passport
MIL ID Card
FIL ID card
MIL property documents (+ notarised document)

The issue is that my MIL has no formal income having been a housewife most of her adult life.
She lives with my FIL and a son.
She owns 2 properties which she takes rent on a cash/informal basis (which is common there) and uses the money to run the household etc. None of this is done via bank transfer so there is no record of money going in or out.

Her property documents also contain phonetic spelling mistakes in her name as a result of translation from Hindi to English. We have a notarised document explaining this.

My question/concerns are:

1. will proof of property be enough to show she intends to return? will the notarised document be accepted?

2. would buying a return ticket in advanced be advisable?

3. her son and my FIL will help her with travel costs, how do i explain this? what documents should i show?

4. she runs the household and very much wants to continue looking after her son and husband when she goes back, is there a way to reflect this on the application?

5. how much money is "enough money"?

I am ready to apply and submit, but these questions are what's holding me back

many thanks in advanced