Alternatives to asking for forgiveness to people i have wronged

I have wronged a number of people in my life, Now I want to settle the scores and ensure i am forgiven.

From those who i have wronged, it is possible for me to ask forgiveness to some of them and pay the debt of some of them.

But there are a group of people, to whom is difficult for me to settle the score.

They are of 4 types :-
1) Deceased Muslims.
2) Deceased Kafirs.
3) Living Muslims or Kafirs, but who are strange to me:- I cannot reach out or communicate to them.
4) Living Muslims who are my non Mehrams.
5) Those who do not know that I have wronged them; and if I say it to them it is gonna hurt them.
I cannot ask for forgiveness to them.

What are the things that I can do for these 5 categories of people whose rights were trangresgressed by me? Is there any alternative for asking forgiveness to them taught by Prophetﷺ ??

Can I do sacrifice on their behalf as an expiation, because Prophetﷺ did sacrifice on behalf of himself and his family?

Can I give in charity in the name of those deceased as an expiation?

Can I make dua for guidance for the living kafirs whom I wronged, because that is the best thing I can do for the kafirs.