Harry Potter and the Looming Deadline

So, my son will have his birthday tomorrow, though his party isn't until Sunday afternoon. This is a big deal. I told him that if he read all the Harry Potter books that I would throw him a true Hogwarts birthday extravaganza. Of course he did it. This is the same child who called my bluff at 5 when I told him that if he raised half the money to get a wii, I would match it. Six months later, he had raised almost 200 dollars on his own..at 5!. He cashed cans collected from our church, home, and my mother's work. He is ambitious to say the least...
I now have 4 days left to perform miracles for this party. I'm concerned. See, I'm a procrastinator by trade. To top that, finances further slowed my progress. I still have signs to paint, half the wands to make, costumes to sew, candy to distribute into its new packaging, and then I have to make the cauldron cakes...the butterbeer... and round up any last minute decor. AAAHHHHH!
If all of that wasn't bad enough.. (I'll get most or all of it done...It's my style) He isn't getting the one present he asked for this year. He knew that I would have tremendous pressure to buy it if he only asked for one thing. He wants a Lego Robotics starter kit. It's 500 dollars! I don't have it! He even tried to sway my vote buy saying,"I'm not doing this for me...I'm doing this for you...I can program them to clean house.." Now I want to order two....Unfortunately, It's not happening this year.
Since I tend to go over the top for party decor anyway, I realize that all the pressure is my own fault. Last year ...in true nerd fashion... He had a Doctor Who themed party... this is the TARDIS I made:

Not to be outdone, My daughter had a Barbie party... She had this photo booth:

This is what happens when a theater major gets to throw children's parties...
Now my plan is to have the children visit Diagon Alley and buy their supplies, go to platform 9 3/4 and hop the train to the great hall, and then visit Honeydukes sweet shop, and (weather permitting) play some quidditch...We will hopefully have a potions class and transfiguration...(origami) and they will all be able to buy and keep their cauldrons, wands, owls, and haul from the sweet shop with the wizard gold they pick up at Gringott's Wizarding Bank.
.... I'll take pics and let you know how it goes. Pray for me, people...I'm going in...