ItWasMeantToBe19
Pikmin
I'm fairly certain it's NLG behind it, mainly because the model being used for Luigi has been adapted and backported into LM2. This means reworking the rig to blink its 3D-sculpted eyes where the original cutscene rig commands just had some textures shift around and animate those blinking eyes instead. The lighting and rendering systems for LM2 on 3DS- and subsequently, the switch rework's updates into using light PBR- are (likely to be) fairly complex and I don't suspect anyone besides NLG would be able to comfortably rework them without extensive documentation and communication.
That seems like a pretty big waste of resources unless LM4 pre production is taking forever.