Moving from boards using Grove Kits & sensors to breadboard

Hi I have been building a local IoT network for a while now and all of my sensors etc are Grove. I have the IoT dev kit for Galileo and RPI and I am moving to creating pre PCB prototypes on breadboards. Is it possible to use the sensors without the Grove Base shield etc, IE will I be able to use them on my breadboard which will have more than likely a ATmega328P-PU as a microcontroller, and ultimately are they suitable for a custom PCB design. The move is A because of costs, B to shrink the projects so I will be able to print my own casings on my Micro3D. Could you let me know if I will be able to use these sensors on the standalone or will I need to buy different sensors, not really wanting to use the Grove Base Shield if possible.

Another problem I have to solve is the RPI is a gateway and relies on Linux, does anyone have any info on what hardware/components I need to get Linux working on the breadboard. The system is an MQTT broker, web server, MySql server, has a TB hdd attached, Motion package for CCTV and Grove Pi+ with sensors, all of which I need to replicate on a standalone breadboard and ultimately a PCB. Any help would be much appreciated.

Can anyone shed some light on this please or point me to documentation of how I would go about using the sensors on a breadboard only setup please.