Startup Business - Tax and Legal Query

This is not related to property investment but a business startup's Tax and legal question. Thought, experts here might have encountered this issue before.

I have recently started a IT consulting company. We also do IT Technical Trainings. I plan to hire contract trainers for short term training assignments of 4-5 days. Some of these contract trainers have existing permanent jobs in other companies or are doing contract with other companies. They will take time off from their existing company to work on these short term training assignments with my company.

My queries

1) I want to hire these contract trainer trainers as "Independent Contractors" and want to pay them full rate and leave "Tax and Super" for them to manage themselves. (In past my wife has done freelancing work for an Australian company in similar way where this Australian will pay full rate (Big American MNC's Australian subsidiary) and leave tax and super for the freelancer to sort out
2) How do I legally protect my company as these contract trainers who might be working somewhere else and will work for my company as well on short 4-5 days contract
3) I have to prepare job contracts for these contract trainers as well. Any recommendation on good and reasonably prices lawyer in western sydney (parramatta area). I need a tax consultant as well. Any recommendation on that?

Cheers,
Manish