Review 2 employment contracts +1 free lance contract

I am a social entrepreneur. I set up a catering company that trains and employs people who are facing barriers to employment.

I have 3 types of contracts:
1) For mothers who can not work during school holidays - Term employment contract
2) For the others who have no children and who can work any time. However as the event industry is up and down, I would like to employ them for a fixed nb of hours with the possibility to increase the hours subject to their approval
3) For the free lancers. They are usually the skilled ones who can look after the others colleagues who need guidance. They are not on the payroll because they know how the system works.

I would need review on the 3 types of contracts. They are already drafted.

Thank you

Kieumy