“Pedants” is accepted as a correct spelling, however, one could easily say “those who are pedant.” I would assume “pedants” is more derogatory, e.g. “you two are a couple of pedants.”
actually the whole source of that "the plural of lego is lego" comes from a source bit of lego branding that talks about how LEGO as a brand name, being a proper noun company name, cannot be turned into LEGOs. This says nothing about the individual pieces being called LEGOs or LEGO and no official publication from the company says anything about LEGOs being wrong when speaking about multiple LEGO bricks.
“Let’s play with LEGOs.”
I prefer the second.