Parallel EEPROM write to with I2C
Using memory as a lookup table is a time tested idea.  Nowadays, there are better methods for controlling LED arrays.

LED array driving is often done with specialized parts.  My go-to part of this sort is AS1115 (it's controlled through I2C).  It doesn't have non-volatile memory.  You would write to it every time you want to change the pattern on the LED array.
So, the EEPROM on the microcoltroller would provide the non-volatility.