For EPF and SOCSO, I am afraid you will have to consult the respective organizations.
I am quite sure your contract staff are not covered by the Employment Act, meaning their salary may be more than 1.5K per month. If so, medical leave, medical claims and annual leave will have to go according to what are stated in the contracts.
KL Siew has put up a sister site by the name of mylabourlaw.net, which is in effect a more user-friendly version of the present popular pesaraonline.net. The site is in the process of being fine-tuned but it is fully functional. You are invited to visit the website at http://www.mylabourlaw.net and give your views or suggestions. Queries can be posted and be responded from there as usual.