Each team should coordinate on waste management and recycling as applicable to their module. Consider talking with food production if you think this is a good possibility.
Electrolysis is a process that can separate water into hydrogen and oxygen.
The rocks and soil on Mars contain oxygen. A process for extracting oxygen from rocks and soil is being developed for the Moon. Space for producing food will be very limited in the Mars colony. Consider making a list of candidate foods for the colony and discuss the advantages and disadvantages of each. The space available on the ship that transports the colony to Mars will be much more limited than even the colony itself.