First of all, the normal preparation period for postgraduate entrance examination is about half a year, but for schools that are particularly popular or difficult to take exams, more time is needed to review in advance, usually starting at the beginning of the next semester of junior year. At this stage, you are not the only one who has many specialized courses, but most schools have more specialized courses in their junior year at the undergraduate stage, so others can take the time to prepare, and I believe you can.
Two, the law major is divided into academic master and professional master. Generally, the academic system of master students is three years, and the academic system of master students is two years. For example, schools that recruit law postgraduates will offer criminal law, civil and commercial law, international law and other majors, all of which belong to academic masters. As you mentioned before, both Master of Laws (Illegal Studies) and Master of Laws (Law) are professional masters, and the restrictions on these two majors are very clear. Master of Laws (Illegal Studies) only allows non-law majors to apply, while Master of Laws (Law) only allows law majors to apply. According to your undergraduate major, you can only consider Master of Laws (Law), and you are not qualified for other majors.
Third, I am not from your undergraduate school, but this should not be difficult to find. In Shanghai, Qi Hong has done quite well in this respect. You can ask.