Hi,
In regard to question 1, you are correct no further relief would be due for personal pension contributions as these are taken gross, you would also declare your gross income before contributions as these are ignored for the purposes of calculating adjusted net income.
Regarding question 2, would be the total rental income minus costs.
Question 3/4, we would advise dividend & interest income below the allowance would count towards net adjusted income.
For further insight follow the attached guidance:
Personal Allowances: adjusted net income
Thank you.