For my private cemetary, I use existing lots. For my Legacy family, I used the lot across the street in Sunset Valley that has the pond and bridge. I go into Edit Town and decorate it the way I want and designate it as a cemetary. Then when there's a death, I just place the tombstone where I want it to be. It won't be an urn because they only appear when the grave is indoors. As soon as you put it someplace outdoors, it turns into a tombstone. The size of it depends on whether the LTW was achieved and how many happiness points they earned in life. The rest of the town doesn't use the private cemetary at all. Everyone else goes to the mausoleum in the regular cemetary like they always have. Living townies do come to visit a private cemetary, though. They hang out at the fountain or sit on a bench and read a book.
One thing to note: Be sure to get all of your decorating done before you place any graves because if you go into Edit Town to change it afterward, the graves will all bounce back into your Family Inventory and you'll have to place them again.
For the still life portrait, get the camera up close and angled toward the easel before you make the selection to paint. Then when your Sim comes to the easel, he'll be in camera range and you can just use "C" to capture it.