Quote from chronocidistOk so it seems like people are suggesting you can use/respond to the second copy of a legendary card before it dies. For example you could play a second flagstone and then tap it before sacking it. Correct me if I'm wrong but that doesn't seem to line up with the text in the article.
"When multiple copies are on the battlefield under one player's control, that player chooses one to put into the graveyard as a state-based effect until only one remains."
In fact it doesn't even sound like they get sacked they just get put into the graveyard. I don't know if that will make a huge difference though.
Since the choosing is a state based effect it seems as though you would never get a chance to, for example, use your second flagstone.
Quote from AnElfInKingArthersCourtCage does not keep loam in the GY, it does prevent them from flame jabbing
you which is their backup plan, it also stops them from flashing back faithless looting, but it does nothing to stop the dredge trigger on LFtL.
Your best bet is to just have 3 to 4 jund charms between your main and side.