Is giving the p60 and contract necessary as I didn't provide this when I applied for my wife's FLR M and that was successful
They are not mandatory, but the guidance does say that they may ask for them, so we just recommend including them anyway, so that if they are needed, they don't have to delay the processing of your application in order to contact you to ask for them.
same with the mortgage statement and council tax bill. I did provide the land register form which I download from the internet.
It is now a requirement to provide 'proof of monthly housing costs' for the visa (I believe this was added in the last 2 years), and I believe you will be asked about monthly costs on the application form... which will be the monthly mortgage and council tax payments. Also, it's a good idea to include the mortgage statement to prove that it is being paid each month (i.e. the homeowner won't default on the mortgage).
I will need to have a look for these, they will include doctor letters, appointments, letters from bank and shopping letters and phone bill statements along those lines.
Examples of acceptable documents are (from the old paper version of the form):
• Letters or other documents from government departments or agencies, for example HM Revenue and Customs, Department for Work and Pensions, DVLA, TV Licensing.
• Letters or other documents from your GP, a hospital or other local health service about medical treatments, appointments, home visits or other medical matters
• Bank statements/letters
• Building society savings books/letters
• Council tax bills or statements
• Electricity and/or gas bills or statements
• Water rates bills or statements
• Mortgage statements/agreement
• Tenancy agreement(s)
• Telephone bills or statements
Do I also need to provide a scan of my parents passport photo aswell?
I'm not sure if this is needed or not. In the past, it hasn't been needed, but I think the online checklist now lists proof of homeowner's identity as a required document. So, it's up to you if you decide to include it or not.
With the updated list which was updated do you think that will be enough for ILR to be successful?
That all depends on whether or not each document you provide meets the formatting and date requirements or not (i.e. payslips and bank statements covering every day of the 6 months, the latest payslip and bank statement, plus the employer letter dated no more than 28 days before the online application date, online payslips verified in the employer letter, online bank statements stamped by the bank on every single page etc.)
At the moment, you don't have your cohabitation documents sorted out yet, so I can't tell you whether or not they will meet the requirement. If you are unable to provide 6 in each name, or they are not evenly spaced, or you don't have 3 official sources, you need to include an explanation for why not.
See Appendix FM-SE for evidence requirements (for mainly the financial documents):
https://www.gov.uk/guidance/immigration-rules/immigration-rules-appendix-fm-se-family-members-specified-evidence