A marketing plan does not need to have all the answers, but it does need to identify all the work to be done to (in this case) do the launch of the new shoes into the market. So while you may make up the market data you "researched" in the simulation presentation, in the plan document you need to identify how you will gather that data, what you want to learn, how you will get that data, who you think your primary customers might be, etc. Companies make the decision to fund new products and their marketing based on the plan, so your target reader is a senior executive with the ability to approve this and let you start work!