I also have/had my middle name added onto my first name by my EZair booking. This is my first EZair booking ever for flights in June to Vancouver Canada. I first contacted AAA who originally booked it and they said contact Princess first as they (AAA) had provided correct info.
Outside of Princess operational hours I reached out to the Airline, submitting my passport info at their request. That process may take 2 - 3 weeks.
Today, I contacted Princess Ez-air (option #4) and James handled my request in 15 mins. 10 of which was him doing tasks while I was on hold. He said "there is no need for a middle name, this is typically why the names are appended together." He had no problem changing the booking to remove my middle name, carefully spelling out my correct first and last names. I can see this now reflected in my EZ-air booking. There was no need to re-book, re-fare or have change fees.
After reading the unfortunate difficulties others went through and the comments to "not worry" "It's fine" ahead of my travel I'd like to stress I'd rather be stress-free. If you still have a issue please try again, maybe you'll be lucky enough to get James.
Hopefully in the future the software/3rd party situation will resolve these discrepancies.
Happy Cruising people!