Since the possibility of disputes is always present your agreement must include a place to cover how any disputes will be handled. This way everyone has already agreed to how these disputes are to be taken care of and cannot argue the point and cause further problems for the rest of the members of the venture. This may end up being the most important area of your agreement and should be filled out very carefully to avoid any possibility of a legal challenge.
If you are employing staff, you certainly need to implement an Employment Agreement. This agreement should be between them and your business and it needs to be clear and well defined. This is because the last thing you want to happen is for your employee to get upset and then take legal action against your company for whatever reason. The best thing you can do is make sure each of your team is engaged using an agreement that both parties have read and signed and agreed upon.