Print the body parts. Connect them up with an arduino nano and PCA9685 for servo control, MPU-6050 for motion sensing, and 8 sg90 mini servos. Use some 2mm nuts and bolts where you need them (or redisgn it so you don't need them!).
Servo control (PCA9685): https://learn.adafruit.com/16-channel-pwm-servo-driver/overview Motion (MPU-6050): https://playground.arduino.cc/Main/MPU-6050 Servos: https://www.amazon.com/J-Deal%C2%AE-Micro-Helicopter-Airplane-Controls/dp/B00X7CJZWM/ref=pd_lpo_vtph_21_bs_t_1?_encoding=UTF8&psc=1&refRID=VYQ9BSMH8Z8KK72G1WW0