Family visitor visa - Long terms Doubts

[hsmp0804]

Hi,
I am British Citizen (since last 5 years) and my parents live in India. My parents had got their 5 years family visitor visa in 2013 (n 6 months visas 3 times earlier), which is expiring in Sept 2018. Sadly my dad passed away in Dec 2017 and I brought my mum to UK end of Jan 2018. She got a return ticket for May end 2018, which Immigration officer noted when we entered UK.
Next I want to apply for 10 years visa in Oct 2018 so that she can stay in UK for maximum time with me but being cautious with the '6 months in 1 year' rule.
What do you think would be best for her so that her stay in UK (till her visa expires) doesn't cause issue for long term visa?

Q1:
Option 1) She stays in UK till May End and stays with my sis in India till Oct 18 and apply visa.
2) She stays till April end(3 months in UK), stay in India with my sis (May-June -2 months in India), back to UK July-mid-Sept (2.5 months in UK) and apply visa in Oct/Nov from India.
My preferred option in option 2 as she stays more time with me but would seek opinion if anyone has experienced this before or moderator's opinions?

Q2:
Next doubt is: I have a property(owned by me) in India which I have rented out and rent goes to my my mum's account for last few years + rental contract is on her name. She has got another parental property on her name and her pension comes to her account too. Would Rental income of my property going to her account for daily expenses be an issue as HO might see she is financially dependent on me? I guess not, as I do not personally transfer money to her account every month and she get additional pension coming?

Q3:
Overall I need suggestion as what would be best way to keep her in UK for maximum time she can spend with me (long term visitor visa: Visit UK every 3 months?) .

Thanks in Advance.

[Wanderer]

You'll struggle to maintain 6 months in every 12 in the current environment, visits are now seen as a few weeks max not several months which is now construed as attempts to settle/reside.