I've read a lot of contradictory posts about this topic, but essentially what I need is for my Raspberry Pi to act as a WiFi dongle for an ethernet-enabled device. The ethernet device connected to the Pi must be passed through to the same subnet of the wireless AP, as if it was connecting directly (the Pi cannot do any NAT!).
Apart from this, the Pi itself does not need any internet connectivity. Its sole function is to act as a wireless adapter for an ethernet-only device.
With the help of things such as MAC spoofing, is this even remotely possible? I see plenty of products such as a TP link travel router that offer a "client" mode, which I presume the Pi can somehow emulate?