I think that’s a bit over kill… adding too many fields to the database, and too many fields/columns to fit nicely into one row in the regular WordPress content area. Starts to get cluttered really fast!
Each sheet has a full editor for the main sheet description, and in there you can easily put all that information in one place, instead of trying to store that with each task. For most of the sign-ups we do for our own PTA, no additional info is ever needed. For those rare occasions when some task/item needs a bit of extra explanation, that is very easy to add to the main sheet description.
Contact info is provided for each sheet, so it’s very easy for somebody to contact the chairs privately if they have concerns or additional information they want to provide.
There is already a field that lets you choose the text prompt for the item details input for each task, where you could enter things like “what is your shirt size”.