I guess that any icon that would be specific to a certain religion should not be used, even though they might be clear.
I searched for 'funeral home logo' on google to get some inspiration and the most you see is a bird, a carriage or some form of wheat. All seem strange to me as an icon, unless you are tweeting somebody is dead.
Personally I would go with a rose, as I cannot think of another meaning for the icon. But only if it's next to the label, not on it's own.
I guess the only clear icon on it's own would be a tombstone, but feels wrong to me.
Update: I like the top left one on this image
