Welcome to the forum! Get some pics up

These are the rule of thumb for wires off the loom:

Red= Permanent Live
Yellow = Ignition Live
Blue = Auxilliary Live/Electric aerial
Black = Earth

Check it works before you put it back in as sometimes the Yellow and Reds need reversing as the stereos don't match up.

Speaker wires, well an ICE expert may know which is which but just use trial and error!

They are normally a solid colour then the same colour with a line if that makes sense? Or they follow that pattern, so light green will go with the one with a light green stripe?

I've always worked on the principal that the one with the strip is negative.

It's just a process of eliminiation putting them in.

Fade your stereo to the front left speaker, test the wires and fin the right one! Obviously gets quicker/easier as you get towards the last speaker

Good Luck