Spouse or common-law partner in Canada class

[CBarr]

Hi everyone.

I have recently received my Permanent Residency.

My fiancee and I will get married late this September, and the wedding will be conducted outside Canada.

Afterwards we will return to Canada together.

The goal is for me to sponsor her under the Spouse or common-law partner in Canada class.

Currently we intend for her to come to Canada using her eTA (Electronic Travel Authorization).

While she is in Canada we will start her PR application (sponsored), as well as apply for an open work permit in case it is processed faster than her PR.

We understand that while her application is still ongoing she should not leave Canada, and there are no plans to leave until she receives any update for her PR application.

We also understand that it can take some time for the application to be concluded (between 3 months, to 12, and more even).

My concerns right now are:

1. what happens when her eTA stay limit is reached? It is typically 6 months, so how do we go about extending it while in Canada, or can it even be extended? Since she cannot leave at risk of her application being terminated, or being denied entry, renovation by flagpolling (for example) is not an option
2. when she goes through the border the first time should we inform the officer of her intentions and explain she plans on staying for at least 6 months for the purpose of Inland Spousal Sponsorship PR application, or should we instead say she will be staying for about 3 months as a tourist?
3. following the above, since she will be staying under my care, but I will be accompanying her, do I have to write some sort of letter or term of responsibility?
4. most important, is the plan above the correct way of doing this? I understand that there is also the option of applying while she is outside Canada, but we would prefer to leave that as a last resort, so we decided on the above, but we cannot find anything clear for us to understand if the above is the right or best way of doing this