How you want your dead body treated depends, as you so rightly pointed out, on a number of factors that the living often give little thought to. I myself was born into a tradition where burial with a headstone in the cemetery was the norm. The best way to answer the question of type is to ask yourself how those you know and call friends or family would want it. If I know that the majority of those who would want to mourn me know and respect a traditional cemetery burial with a coffin incorporating a Christian service, that would be what I would decree.

You have to know whether people who largely see themselves as secular want to fall back on the religious traditions that still exist. For my part, that's what I would want.

I've been to a few funerals with the classic procedure: Laying out the deceased in a chapel a few days before the actual funeral, individuals visit the deceased in there and say an intimate farewell, communal funeral service in the chapel rooms, communal burial of the deceased with the mourners standing around the open grave and the priest saying last words and the congregation doing their own part. Throw a shovel of earth into the grave or a flower.
Afterwards, the guests cross the road and meet at the restaurant for the funeral feast. Also, a more private open house was arranged for closer relatives and friends in the home of the deceased. I found it very delightful and helpful to be together with others after the official ceremony, and to chat with long time not seen people and have some laughs and get back to normal after so much sadness earlier in the day.

Our tradition also included that every funeral guest/family who attended not only gave a condolence card but also fifty or hundred bucks to lower the cost. We are Russian-Germans and always did it that way (same with weddings). Since a funeral is expensive altogether, this helps the family to cope with the financial aspect.

When my mother died, one scene remained very vivid in my memory. Our neighbour, who was already very old herself at the time, entered the room where my mother lay in state before me, leaned over her, kissed her on the lips and said: "My Lindadchen, I will miss you." (giving her the nickname) My heart opened and I rejoiced at this simple and heartfelt statement.

I find that Christian traditions are still the best and I wouldn't want them to vanish. People are very careless about all this when they are young, indeed, and will become even more careless when nobody remains who teach them some important traditions.

If you find that it pollutes the environment you can choose to be buried with clothes and coffin which decay easily. I am sure there are solutions to that.

I hope that was helpful.
Greetings.