How to make customized what if condition for checkout

[lchristina]

Do you think I could customize the checkout page so that it caters 3 different scenarios according to which product(s) I check out with?

1. Generic checkout

2. Checkout involving any product from brand that I partner as dropship - I need to remind them at the checkout that the shipping will come in two separate batches (one from myself, another from the dropshipper) and he/she needs to pay extra fee on imported duties

3. Checkout with one province field frozen (e.g. Ontario) in the recipient address field if it involves any product from a brand that I agree not to ship to a specific province

I have no clue if the above scenarios could be customized? If so, how could I do so? There seems rarely any discussions on the web about these so your advice are highly appreciated!