Monash is already a University on its own. What do you mean which uni it collaborate with? You can exchange to Monash Australia.
Monash provides double major for the Business degree. You can choose to major in Accounting and Finance for your degree.

Monash doesn't need to collaborate with other Unis in terms of offering a Degree. In the first place Monash came to Malaysia due to a collaboration with Sunway then MOHE invited to open a full fledged campus in Malaysia. It's already a godd University which is part of Australia's group of 8.

Double Major means you have two concentrations in your Degree, usually in a business degree you'll be able to take enough subjects to do 1 major plus enough electives to form another major or two minors. You'll only get one degree but in your transcripts it'll mention you majored in this two fields if you choose two major in two things.

Double Degree means you are doing two degrees at the same time for example a Bachelor of Business and Bachelor of IT. You'll still do the same amount of subjects as somebody doing one degree but it'll take longer for you to graduate since you need to fulfill the requirements of both degrees. You'll be doing equal amount of subjects for each degree each semester. For two degrees that each would take three years to graduate from would take four years to finish if done as a double degree. At the end when you graduate you will get two degrees.