UK spout visa living away from home mon-fri

Hello. I haven't been able to find any information on my situation and was wondering if anyone here was in a similar situation and had been successful in getting the UK spouse visa.

I am a British citizen that is married to a Japanese woman.
We got married in Japan however did not have a wedding ceremony.
We have 3 children. I have adopted her daughter (10yr) over there and we have 2 sons together. My 2 sons (4yrs and 18months) have got their British passports so my wife needs to apply for a spouse visa with only one dependent (my stepdaughter).

I came back to the UK in September 2019 by myself after securing a job in London that meets the minimum financial requirement with one dependent (£22400).
I will have accumulated 6 month's pay slips by March 2020 so I will be able to do the application then.

We have decided that we do not want to live in London as it is too expensive and we would like to live close to family in Newcastle. My mother who lives in Newcastle has cancer, so it is important for us to live close by. We would like her to spend quality time with her grandchildren as much as possible.

I am trying to figure out if it would be possible to use a 3 bedroom property with 2 living rooms in Newcastle jointly owned by 2 of my sisters in the application.

They both have given permission for us to live there for as long as we need to find our own place. Only one of my sisters lives with her husband in the property and so they will be occupying one of the bedrooms. The other sister lives with my mother in a separate property.

Would we meet the adequate accommodation since there are 2 bedrooms available and 2 living rooms of which one can be turned into a bedroom aswell?

My biggest concern is that I will need to stay Mon - Fri in London for work and would only be staying with my wife and children every weekend.

I wonder if this kind of situation are rejected or not?
Were any of in a similar situation and were you successful in obtaining a spouse visa? Did you go through a solicitor to strengthen the application?

Soon after they arrive to the UK I would be looking into finding a job in Newcastle. Or would it be safer/better to find a job that meets the minimum financial requirement in Newcastle and apply after accumulating 6 months payslips again?

As I am only borrowing a room in London I cannot use it on the application and also cannot afford to rent a property that meets the requirements. Even if I were to financially manage to rent a property privately in London, I would be stuck in a minimum contract making it difficult to move back to Newcastle straight away. Also I wouldn't want my daughter to switching schools just after settling in

Ideally I would like to get my daughter into school for the new academic year (September 2020) and so applying for the visa after moving back to Newcastle might mean she misses out the start of the new year.

Any advice would be much appreciated.
Thank you in advance.

is the property big enough? - Yes.( see xxxxxxxxxxxxxxxxxxx ) if you really like reading regulations.

Does it matter that it's provided by family? No.

Working in London Mon-Fri --> You're okay. UKBA will be interested in whether the marriage genuinely subsists and you intend to live together, or whether you have de-facto separated. If all your personal bills, bank statements, employment docs etc etc are going through / starttp go through the Newcastle address that's great. Use the newcastle address for your application. Using addressed docs etc you can show you're living there, and intend to live there together. The fact you sleep on a couch in London when working isn't indicate that you either have separated from wife and children or intend to live apart permanently.

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