I have always been told "There is never a guarantee that you will get a visa, or visa extension", I arrange my life with that in mind.
I have no idea what you mean by this, but I would be very careful about that "arrangement", we all know that unless you have authorization to work, you should not.
Your visitor record should clearly state the terms of your stay (on mine it specifically excludes working, so I do not work). You would not want "the arrangement" to come back and bite you.
Don't forget that your proof has to convince Canadian immigration, the other parties don't really count.
Sorry if I wasn't clear. I have explained this work situation to multiple Canadian immigration officials (while crossing the border when traveling and while asking for information related to my visitor record and my tentative application for PR) and discussed it with an immigration attorney. No problems. I was concerned also that there would be an issue with working from Canada while I'm here, but I've been reassured that this is not an issue, and I've concluded that it's important that I explain this because it provides evidence that I'm not attempting to enter the Canadian workforce. If letters from both my US employer and my Canadian collaborator along with pay stubs from my US employer don't convince them that I'm in a stable position in the US with no intention of seeking work under the table in Canada, then I don't know what would. I can't exactly claim that I don't work, because I do.
I am hoping that someone who has applied for a second extension to their visitor record might share their experience with me. I would find it very helpful to hear from someone who has legitimately lived in Canada on a visitor record while going through this process and could provide insight about what happens if the process takes longer than a year and the second extension is required. Thanks so much.