Order from that updates based on the date

Currently Gravity Forms has a Product Field and an Option Field for selections. Product Fields do not support Checkboxes because there is a Quantity associated with a Product and it would make it difficult to have Quantity integrated if the Product was a checkbox field. So currently a Product can be a Single Product or it can be a Drop Down or Radio Button selection.

Options can impact the price and they do support Checkboxes for the user to pick multiple. This is because the Quantity impacts the Product itself so it doesn't come into play with on an individual Option basis.

If you configured your form so there was a base product with a base price, even if that base price is $0.00, you could then use an Option Field so they could select individual options that could then add to the price. Just keep in mind that the Quantity would impact the overall Product. For example, if they picked 3 options that means the Quantity would be that product and those 3 options times 3 because the Quantity was 3.

Gravity Forms can't do conditional logic based on date, so it's not going to be able to do what you described as far as showing and hiding additional items based on date. Conditional Logic only works on drop down, radio button and checkbox fields.

So the date selection would have to reside in a Drop Down field so it wouldn't be able to be a datepicker and the dates would have to be pre-defined which may not work for what you are trying to do.

So i'm not 100% sure if Gravity Forms would be ideal for what you want to do. It just depends on if you can work with the available toolset and make some compromises in how things are put together.