As a seasoned embedded systems developer, I am well-versed in critical aspects like PCB designing (using tools like EagleCAD and Proteus), I2C and USART communication, and STM32 microcontrollers. My familiarity with STM32F103C8T6 and STM32F103RBT6 is particularly relevant to your project. In line with your brief, I assure you a compact rectangular PCB layout where the Melexis MLX90614 temperature sensor, VL53L0X distance sensor, and the STM32 microcontroller communicate seamlessly through I2C.
Moreover, my diverse experience in industries ranging from telecommunications to smart healthcare ensures I appreciate the significance of prototyping in your project. An intricate understanding of embedded C, C++, Python for microcontrollers like Arduino, ESP8266, ESP32, AVR, ARM, and Atmel sets me apart.
To sum it up, my depth of knowledge in hardware-software interfacing using different platforms makes me an asset to any prototyping project that requires precise control over its components. I have recovered complex embedded systems from deep bugs and this would be my expertise treasure in guaranteeing optimized performance and reliability for your project. Look no further as my compact design capabilities coupled with vast experience make me the best choice for completing this task effectively.