1. When faced with the current economic downturn, the company may have no choice by to take such drastic measure in order to survive. For for the workers, salary cut is a breach of contract. What the workers should do is to bring the issue to the Industrial Relations Department for them to help to find some amicable solution to the problems.
2. Yes, they can do that if they want to.
3. As stated in 1 above, you and some of your colleagues can bring the matter up with the Industrial Relations Department.
4. Since those with salary above RM1500 are out of the scope of the Employment Act, they will have to negotiate themselves for better deals in this respect. Although such practice is not illegal, but to me it is not a wise practice.
5. It depends on whether the resignation or sacking is with immediate effect without notice. If without notice, the party concerned will have to pay a month's salary in lieu of notice.