The project started with ordering all the necessary components. After receiving all the necessary material I was able to design the housing. Now when the project is ready I have to admit that the idea to solder everything together with wires is not the best idea. The overall design is very large and could be drastically reduced if I would design a simple PCB.
Although the space was limited I managed to fit all the wiring inside the designed housing without needing to make it larger.
For communication NRF24L01 module is used. Theoretically one could get up to 1km range with it, however I assume the practical limit is around 100 meters.
Overall the walkie-talkie functions as expected. Nevertheless, the electrical noise in the audio output wire causes noticeable background noise and that is slightly disturbing. After using a well shielded wiring I was able to improve it, however it is still present.