So there was one month from the start of the project, until the schematic should be handed in. It sounds a bit late to worry about the design during the last two days - work could have started on the schematic while you waited for the modules to arrive. Directly you made the decision what modules to use, you would know what datasheets to look at.

As a matter of fact - the choice of modules is normally made based on what performance you want, and what electrical interfaces you want. So if you made the module choices because you wanted to interface using two UART, then you could have selected a suitable microcontroller and started the design of that part even before deciding exactly which GPS or GSM module to interface with. The only potential open issue would be if the GSM and/or GPS modules would have a different logic level, possibly requiring you to insert a logic level shifter between the UART signals and the module.