I'm planning a trip to Universal Studios Orlando in March with the kids - they want to see the Harry Potter parks. I'm assuming first of all that the Universal 2 park pass includes both the Harry Potter parks - or are there other Universal parks there as well?

Anyway, I got the Chase Saph Res card and have the $300 travel credit available. Also, I want to pay for at least $150 of the ticket costs with UR points so that I'm break even on my $450 annual fee. I've never use the UR portal before, but I did find the Universal Studios 2 park pass for 2 days starting at $220 per adult. However, there are several options.

First there are the Europe resident tix which cost more -$308. Not sure why anyone would choose that option.
Then within the regular 2 park tix, there is "2 park-2Day Base 2 days Free" for $220 and 2 park-"2Day PTP 2 days Free" for $259 each.

Are these tickets good for 4 consecutive days or do the 2 free days have to be split up later? "Special Offer - Book a 2-Park, 2-Day ticket by May 3, 2017 for travel through May 28, 2017 and receive 2 days free! - BOOK NOW!"
What is the difference in the Base and PTP options?
Will tax be charged? I've run thru the purchase nearly to checkout and haven't seen a reference to tax yet.
Also, how do I select the dates on the tix? it says: "Tickets are only valid on selected date of travel.Universal Orlando operating hours normally begin at 9am and closing times vary" But on the Univ Studios website the tickets just say they can be used in a 7 day span once you first enter the park. Are they really date specific?