The thing is, to those who have died, it doesn't matter where they're laid to rest or how they were laid to rest. In other words, if they did have funeral wishes, they'd have no idea as to whether their instructions were carried out and quite frankly at that point, they certainly wouldn't care.
When they're no longer here physically they do live in our minds and they live in spirit. Their legacies exist as long as the memories of them exist. This is why it's so important to share family stories, even write some down, so other generations can know about their ancestors.
The moment the memories are forgotten, the legacy is forgotten. No doubt the ripple affect in how we live our lives will continue to roll on with most people not even knowing why they are where they are. They won't know all it took to get them to where they are now, like us, they'll mostly take it for granted. So the fact is, even when we no longer exist in memory, the impact of our existence lives on whether good or bad.
Anyhow, we're only here a short while and what we do does matter now and after we're gone. Part of our existence generally fades after a couple of generations, that's just the way it is, but the fact is our lives on earth will continue to have a ripple affect pretty much throughout the ages; once gain, whether it's a good influence or a bad.
I think that every day we should remember this important fact. We do matter. What we do and say does matter. The impact of how we live our lives will continue long after we're gone. Make it a good one. Carpe Diem!