Hi,
We can use Wifi module board in order to meet your WiFi requirement, We can use either ESP8266 or ESP32 If you want additional Bluetooth features. both of them has already included microcontroller features and has Arduino core already, to accelerate development process.
I known several RF module features and this kind of board is my daily activity. I know how to managed WiFi module based PCB like this.
I have designed PCB since 2012, and has done lot of projects for various application, from Hobbyst to Military purpose.
I will use either Kicad or eagle for this project, and I think 2 layer is enough. just tell me your detailed specification over chat, and let's working on this project. I can provide you manufacturing file and Bill of materials for this project.
Best Regards,
Rijal