Is 3.5mm jack to female Apple Lightning adapter technically possible?
Lightning is a purely digital interface (unlike USB-C which does have the capability to output analog audio directly and is replacing Lighting on new products). So the Lighting connector on the EarPods will need to contain:


A DAC to convert the interface to analog audio in order to drive the speakers inside
An identification chip of some sort to tell the host device what's been plugged into it and what its capabilities are
An amplifier circuit powerful enough to drive the in-ear speakers


For reasons of size,  these functions will most likely be combined into a single physical chip.

What travels down the cable from the connector to the in-ear parts will be analog audio - indeed, the alternative version of the EarPods has a 3.5mm stereo jack plug for use with any audio device that has a headphone socket.

The Lighting interface also has power pins that supply the interface circuits in the EarPod connector.

So to achieve your aim of connecting a set of EarPods with a Lightning connector to a 3.5mm analog output on some other piece of equipment, you would need the following:


ADC converter to digitise the audio
Processor to control the ADC
Lighting interface port of some sort to plug the EarPods into
Software to run the whole thing
Power supply


Is it doable? Yes, given enough knowledge and time. Is it cheaper than buying a set of EarPods with a 3.5mm plug? No. Is anyone ever likely to make such a thing? Probably not as the previous answer shows there would likely be little demand. Can you do it with a passive adaptor? No, as you have to carry out conversion of analog signals into digital signals.