LCC 1, 2 & 3 is not compulsory and all of them is the foundation of being a professional in accounting. So you can skip not only LCC 1 & 2, but also LCC 3 too to save money and time. Most candidates finished LCC and then study HKIAAT or QP, you can directly study HKIAAT or QP and ignoring LCC.
But please pay attention that some courses for HKIAAT or QP are revision cources, which require you having some basic knowledge in accounting. If you have condifence to handle it, please ignore LCC.