Sounds good. Updated.
Looks good. We just need height/length/weight and languages (if any).
Well we aren't converting Mothra, specifically, so we've got a bit of wiggle room.
How about... "An insectoid gargantua cannot speak, but may understand a language."
GAH! Let's just leave it vague...
"An insectoid gargantua cannot speak, but scholars believe it may have a language it uses among its own kind, or even between other gargantua."
That way, it can speak to "Godzilla" if the DM is so inclined.
Ready for the larva?