Rinse the mussels several times. Place in a bowl. Cover with water. Soak in the fridge for several hours.
Clean the squids (see how) and cut into chunks.
Cut off the antennae of the shrimps. I do not recommend peeling the shrimps.
Take a shrimp and pierce with a toothpick between the first and second segments of the shell counting from the head. Twist the toothpick then pull out to remove the black thread that runs through the length of the shrimp (see the technique). Alternatively, cut the shell along its back to expose the black thread to make it easier to remove (see how). Repeat with the rest of the shrimps.
Take the mussels out of the fridge and rinse again. Pull off the beards.
Boil six cups of water in a pot with two tablespoons of salt. When the water is boiling, dump in the mussels. Once the mussels open, scoop them out and set aside. Optionally, when cool enough to handle, you may break off and discard the empty half shells.
Scoop a cup of the hot mussel broth into a bowl. Drop in the saffron threads. Leave to soak for five minutes.
Pour the rice in the rice cooker. Add the mussel broth and saffron with the soaking liquid. Cook the rice as you ordinarily would in the rice cooker.
Meanwhile, heat half of the olive oil in the paella pan.
Over medium-high heat, cook the shrimps hot olive oil with a teaspoon of salt and a quarter teaspoon of pepper. DO NOT OVERCOOK. Two minutes on each side should do it. Scoop out and set aside.
In the remaining oil, still over medium-high heat, cook the squids with a teaspoon of salt and a quarter teaspoon of pepper. Again, DO NOT OVERCOOK. Two to three minutes with occasional stirring should be sufficient. Scoop out and set aside.
Turn down the heat to medium. Pour the remaining olive oil in the paella pan. Saute the garlic, onion and bell peppers with the paprika and bay leaves.
Turn up the heat to high. Scoop out the cooked rice directly into the paella pan. Add the peas. Stir. Taste and add more salt and pepper, if needed.
Spread the rice evenly on the paella pan. Arrange the shrimps, squids and mussels on top. Continue cooking over high heat (a little scorching at the bottom gives the paella a more authentic touch) for three to five minutes or just until the shrimps, squids and mussels are heated through.
Sprinkle the seafood paella with thinly sliced basil leaves and serve immediately.