Adjusing any part of the functioning of a non-isolated mains-powered undocumented processor that has an undocumented program operating is bound to be a serious challenge.

The OP states the IC has 12v supply, Maybe not a Micro after all,
In any case, it would be much simpler - easier to start a micro from scratch.

 

I think the diode will be a zener diode to regulate the 12 volts down to 5 volts ( Or 3.3 volts.) for the micro. A picture of the etch side of the board would be a GREAT help to conform that the posted schematic is correct and to see if the pinout matches any common micro.
You say " All I want is the colors to swap over a 7 - 10ish second period. " but you have not yet said if the colours are just the three colours of the LED or mixes of the three led colours to give more colours. If someone is prepared to write the code for you they need to know EXACTLY what you want.
Les.

 

Update:
Schematic and sequence plot, fade in and fade out is done ny 253khz PWM signal.
Can't be sure of the Micro, however.

 

Late Update.
OP eventually received modified Micro version.
A pic1618313 had to be used due to the PWM hopping across three ports.
Also time picking up the required vagaries of MPLABX ver5.35 whilst using ASM !

 

I have many LED projects using LEDs that have a microcontroller built inside the LED. Color Changing LED products are sold at Thrift Stores and online or separate LEDs with all LEDs and the entire circuit are sold online, look in Google.
Here is a color changing LED product I found online:

 

This app, needed a fade in and fade out time Of three in turn.

 

Some of my my single 5mm LEDs have RGB colors that fade with slightly different fading times resulting in colors adding producing thousands of colors. Other RGB LEDs fade one color at a time.

 

Presumable you would need some else in order to sequence them at set times?