1. Check that your power supply can deliver enough current (and voltage) to your LED strip. Current requirements increase in proportion with the number of LEDs you want to illuminate, and the color and brightness they are set to. An insufficient current can mean that the internal red/green/blue LEDs are not illuminated correctly and thus the colors are not as you expected.
2. The absence of a Slave Select or Client Enable pin means that the APA102 takes full control of the SPI interface. This means that you cannot connect more than one SPI slave to an SPI pin (unless you employ additional electronics).
3. First, check that your logic level converter is connected correctly. Secondly, it's possible that the logic level converter cannot convert logic levels fast enough to keep up with the SPI interface. Try lowering the SPI bus speed.
4. We use the PIL (Python Imaging Library) to create an in-memory image representing what we want to display. We then send this image to the OLED display...