Bring a large pot of salted water to a boil.  

Rinse the seafood well (especially the scallops) and pat dry with a clean dish towel or paper towel. Set aside to sit at room temperature while preparing the rest of the dish.

Add the pasta to the water and cook until al dente. Drain the pasta, reserving the pasta water. Prepare the sauce while the pasta cooks.

While the pasta cooks, in a large frying pan over medium heat, add 2 tablespoons of the olive oil and 1 tablespoon of the butter. Once the butter is melted, add the shallots and cook until fragrant and transparent, about 4 minutes. Add the 2 cloves of crushed garlic, and cook for about 1 minute, stirring (careful to not brown or burn the garlic as it will become bitter). Add the white wine to the pan, stir, and cook until reduced by about half.  

Heat a large frying pan on medium heat, add the remaining 2 tablespoons of olive oil and 1 tablespoon of butter along with the 1 clove of smashed garlic, season the seafood with salt and pepper, and cook in batches, starting with the scallops, (careful to not overcrowd the pan or they will steam, not sear) on each side until the scallops are golden brown (the time will depend on the size of your scallops, but about 2 minutes per side) and the shrimp about 2-3 minutes in total, until they just turn pink and are cooked throughout. Set the seafood on a plate, tent with foil to keep warm, and finish assembling the pasta.

Add the cooked pasta to the shallot white wine sauce, turn the heat to medium, and add the peas, parsley, Parmesan, lemon juice, lemon zest and season with salt and pepper to taste. Toss with tongs to combine, adding extra reserved pasta water to loosen the pasta if needed (I always add a couple of ladles of it) and cook until the peas are done, about 1-2 minutes.  

Transfer to a large platter or serving dish, top with the seafood and serve immediately with extra Parmesan on the side.