I'm not familiar with the detailed ins-and-outs of the new requirements for international flights in and out of the US, but I suspect you may be right - the Canadian bit could be an issue.
I would call (or better-email) the embassy and ask the following questions:
1) 'Can I enter the US in a private aircraft on the Visa Waiver Scheme'?
2) 'Can I do as above while acting as as PIC ?' (assuming here that YOU will, in fact, be PIC on that flight - if not, then disregard).
Get the reply in writing and have it with you when undertaking your flight (assuming they say 'Yes, it's OK').