Its always a bit annoying that early teardowns are often lacking up close shots of most parts except the cpu/gpu, given they are in many people's hands now it shouldn't be too much longer till we see full hq images of the whole board, but yeah the wifi is probably under the shielding as mentioned, as the wifi antenna plugs in up there too.....oh well guess we will see
Ok seeing as it's probably highly inspired from the shield, it's probably the audio controller, the shield one is AL5639, the whole console seems to have been a nice way for Nintendo and nvidia to pool resources, they probably took advantage of the existing parts pool at their disposal