Tell us about yourself!
Yes, yes, and yes! If your Arduino has a USB port, then you don't need the converters to protect the OLED display from 5v. You also don't need them anyway because you aren't using the display. It will output to serial.
I've noticed that you go stuck with the small font. There's since been an update to the OLED library. Get the latest version and add "#define INCLUDE_LARGE_LETTER_FONT" to your INO file.https://github.com/sparkfun/SparkFun_Micro_OLED_Arduino_Library/blob/master/src/SFE_MicroOLED.cpp#L48
DIY Digital Compass (for your car)
Raspberry Pi Solar Weather Station
Easy Generator to Home Hook Up