Clearly, you should also know by now what format or medium the project is to be in. If you don't have the answers to these questions, well, fair enough perhaps, as it does say 'brief', but if you can't answer those questions by the time you complete your project proposal, then you're well behind schedule. OK, so you may have to make adjustments in due course, but things should be pretty definite by this stage. Resources available Bear in mind that your finished artefact has to be of publishable quality - it should be usable as completed by you. Make sure you discuss your intentions thoroughly with your teacher - she may well know of resources which hadn't occurred to you.
People can be resources too.
This should not be a problem by this stage. Pretty much all you should have to do is copy the details from your year planner. You should nevertheless have a pretty firm idea at this stage of how you intend to test the project. Your plans at this stage should at least be relevant and sensibly chosen.