I've been up a few times thanks. Just wondering what system you found most practical for the future when the kids are older. I have short roped my eldest in the past but now that he's a lot bigger and heavier, I don't want to do that anymore.
The best approach to West Lion really is to come armed with rock climbing skills and take a helmet to protect yourself from accidental rock fall. You can use tree trunks as a natural anchor and that is all there is up there in terms of anchors. There are no reliable anchors on the first exposed slab traverse. If you have been there a few times with your kid, why don't try a new destination with your big kid like Sky Pilot? At least there are new reliable bolts and rings at Sky Pilot's Pink Slab and crux that are totally reliable and can be safely used to belay your kid especially on the way down.