I saw all the important information there, if not those exact documents.
The big question is -- am I disturbing a painted surface in any meaningful way? I'm smoothing down the acrylic (?) mural. There are ways to do this without disturbing the underlying paint at all. And "disturbing" in most of this stuff seems to be a bigger deal than what we're talking about here. They have pictures of holes in walls, and they're talking about tearing down walls and renovations. Not basically washing a wall.
When I do find something that is close to my situation -- though again, I haven't found anything that covers it exactly -- it seems pretty non-alarmist. For example, from your second link, it says:
Consumers may choose to have a testing laboratory test a paint sample for lead. Lab testing is considered more reliable than other methods. Lab tests may cost from $20 to $50 per sample. To have the lab test for lead paint, consumers may:
Get sample containers from the lab or use re-sealable plastic bags. Label the containers or bags with the consumer's name and the location in the house from which each paint sample was taken. Several samples should be taken from each affected room (see HUD Guidelines discussed below).
Use a sharp knife to cut through the edges of the sample paint. The lab should tell you the size of the sample needed. It will probably be about 2 inches by 2 inches.
Lift off the paint with a clean putty knife and put it into the container. Be sure to take a sample of all layers of paint, since only the lower layers may contain lead. Do not include any of the underlying wood, plaster, metal, and brick.
Wipe the surface and any paint dust with a wet cloth or paper towel and discard the cloth or towel.
It doesn't say "use goggles, mask, and gloves while doing this." It doesn't say "this is an extremely risky procedure and should only be done by a trained professional" -- and that's when they're purposely going down the the bottom layer where the lead is most likely do be, and really
disturbing it. It just says wipe the surface with a wet cloth or paper towel and discard the cloth or towel. That doesn't seem like they think it's a huge deal, and what I'd be doing is less disruptive than that.
That one also speaks well of "wet methods."
I'm getting a little frustrated because apart from Joe (thanks again) I'm getting lots of concern
but not recommendations. What do you guys think I should do? Leave the whole shebang as-is? (The links I just read reaffirm that doing something about it is actually a better idea, rather than letting it decay and flake.) Get a contractor to deal with this? Do the 1/4 inch sheetrock? Forget about the mural and just paint, outlines be damned? Do the spackle thing Edgar suggested to smooth out the mural without disturbing anything? What?
One of my biggest flaws is erring on the side of caution, that's why the room has sat there deteriorating for six years. I want to move on this, and am asking for advice on how to best do so.