For the grieving thing, they really don’t need that much land to do it. I think the other commenter is generally correct, though.

When it comes to the wildlife thing, it’s all just low-height grass monocultures and maybe a few trees if you’re lucky. That’s not really doing the animals any favours, they need taller grasses and bushes to hide in, and more tree density than a cemetary allows for. A dense urban forest with a footpath would be far better. An example of this is Montréal’s Parc Angrignon, if you want to check that out.