for my schedule c, will the irs see general line items (eg., supplies, expenses) or all the specific items (toilet paper, AMTC membership, etc.)?

Your tax return will include whatever detail you enter.  If you list expenses for individual items (e.g. toilet paper, AMTC membership, etc.) that information will be included, and if your return is reviewed, will be viewable.  For you business expenses, I suggest you summarize by expense category, (e.g. Office Supplies, computer expenses, subscriptions, etc.)