We don't want the customer to have to add the item to the cart, then go to the cart to see the discounted price. It's not a good customer experience, especially since no coupon code is needed in this promotion.

And for the items that should not apply at all, we'd like to exclude them from the discount all together. Is this possible, if so how?

If the item in the email is all ready discounted, like Orig. is $100, sale price is $80, 50% off the $80 would be $40, so in the email we would put Orig. $100 strike through that and put $40 - WE WANT THIS SAME THING TO BE REFLECTED ON THE PDP.

The problem is that we send emails about these promotions and the emails have multiple items in them, some original price some discounted. Let's say the discount is 50% off. If the item is original price $100 we would strike through that in the email and put the sale price of $50 - WE WANT THIS SAME THING TO BE REFLECTED ON THE PDP.