Arduino R3 with separate ESP8266 or Arduino ESP8266 Wifi Board?

Alternatively you could continue to use your "Arduino esp8266" board, whatever that is, and replace the adxl335 board with one that has an i2c interface and requires no analog inputs, such as mpu6050, or something similar and maybe better.

Or continue to use your esp8266 and your adxl335 and add an ads1115 i2c analog to digital converter.