I've done dozens of projects just like this. Check out my portfolio. I would do your project using php and for dynamically creating the PDF file I would use FPDF. I've done this hundreds of times including recent projects.
For the billing, also check my portfolio, I've worked with over a dozen merchant accounts including PayPal, Payza, [login to view URL] and FirstData to name a few. I have also done split payments just as you described.
I will setup a simple members area for your workers and clients to use for the at the door ticket reconciliation so that even the most brain dead worker will be able to use it. I will also create the ability to add events and then each event has it's own page and it's own order button.
I'm ready to work on this right away. Let me know if you have any questions. You can send me a message and we can chat and I'll answer any questions. I can have this done in a couple of days from when you do the escrow. I ask that you put the entire amount into escrow so I know it is there and I won't get a penny until the job is 100% complete and you are satisfied. This way you know I will finish the job completely and not run off after I get my first payment, plus you will know that I will knock the project out quickly.