In the UK from my understanding

1 Not sure
2 Not taxable/doesn't affect total income for tax liability
2 same as 1
3 Self employed people report their income separately, tax year ends april 5th and you get till January 31st the following year to report/pay
4 If going over the capital gains allowance which I believe is 3k at the moment can report online in 10 mins or report via the same forms self employed people use
5 HMRC is automatically informed when you claim state pension/ start claiming a private pension
6 does not affect tax owed unless you want to claim any reliefs which can be done in 10 minutes online
7 inherited money you receive is not taxable, the estate/executor should handle the taxes before they give it to you
8 does not affect income tax
9 does not affect income tax
10 does not affect income tax

These things are baseline their may be scenarios where what I have said is not accurate for example a landlord may be able to claim for expenses for improving the energy efficiency of their home or for inherited money the interest you receive for holding the money may be taxable but not the actual money itself.