Adding ethernet jack and transformer to device designed without one
The normal and only way to make it by keeping the signals within required levels would be to remove caps and the 49.9 ohm resistors at the wireless module side so that magnetics are directly connected to only single set of termination and the Micrel PHY.

For test purposes, I have put transformers and 8P8C jack without termination after capacitive coupling and it works with some devices and not with others, so I can't recommend it.

So at minimum, just put a magjack in place of the wireless module.

The capacitive coupling is only meant for special links between boards, so the Micrel chip may have specially configured settings for this being a capacitive interface - usually capacitive interfaces are forced on with 100Mbps full duplex settings, so there is no auto-negotiation available, as autonegotiation and 10Mbps does not pass well over the caps. If this is true, and you can't change those settings, it may not work well with standard devices.

If you really need to make it work, an overkill solution would be to replace the wireless module with module that has a switch chip that has one true magjack port for the actual Ethernet and one port configured for the capacitive link.