UK Standard Vistor Visa Clarifications - Filling form for my wife and two children

I am an Indian citizen applying for a Standard Visit visa (tourism) for my wife and 2 children (aged 15 and 9). I already have a Type-C 2 year visa. Some questions I needed clarity on for the application:

1. For the Question saying Give details for the main purpose of your visit: Should I just mention Tourism/Sightseeing like I have done (for my kids, I have mentioned museum visits as well, since they love them) or is there an expectation for more details. Understand it may be a generic one considering the box size, but still wanted to confirm.
2. Under income and expenditure, for the question on any other income or savings (besides the salary), should I mention no for my wife (have done the same currently, since the employment income is the main). Ideally there are investments in Fixed Deposits and insurances, but there is no earning unless you liquidate them. On reading posts, I understand I will have her carry her last 6 months statement from her salary account and maybe copies of these FDs. Will that work

3. Question on How much money are you planning to spend..a) Should my wife mention the entire amount here on behalf of the family or should I allocate say 1/5 each to both my kids application. Infact for the question on kids, should me and my wife split the question on who will pay for the cost of the trip..so for my daughter, my name can be given as taking care of her expenses and for my son, my wife can give her name. Slightly confused here, since while my wife can be a primary, since I am also travelling, I wanted to give the impression that we both will manage the costs for each other as well as the kids. Also, if we can do so, should we carry both our financial document copies with us.

   • 3a. There is also a question on how much you spend in a month. With the kids ideally it would be an approximation since they get the pocket money and other day to day needs from us (I am sure UKVI understands, but dont want to put an answer as an assumption, so have put some approximate costs like GBP 100 or something)

   • 3b. Since the amounts asked in the financial information can be mentioned both in GBP and INR, does it help if I mention the same in GBP for ease. I know this may be a silly question, but still asking.

4. Where do you plan to stay in the UK - since I don't have a booking yet, should I just mention that we plan to take up a hotel somewhere in London or do give a option e.g. Holiday Inn
5. For the question on Travel History - With an option of New Zealand, US, Canada and EEA. We actually visited the US and Canada last year, however since its a combined question, when I mention US, I am only allowed to choose either of them, hence I have to go with US since thats where we spent the most time. On moving ahead, we need to mention countries besides these, which we have done, however cannot mention Canada anywhere. Do I need to mention that in the additional information.
6. Extra Information - What all can be put which supports your application...as I have now I have kept it blank

Thanks for your support in advance.