Sorry for totally misunderstanding your question. Below are my answer to your various questions:

1. You can book through UA and provide your Aeroplan number. You will gain SQM and SQS for AC (but not SQD).
2. If you have AP status, you will be able to use your privileges in UA ticketed and UA operated flights, depending on whether you are 35K (*A silver) or 50K or above (*A gold).
3. Assuming you are 50K or above, you will have access to United Club with your UA BP.
4. You will get your full AP point bonus if you select this as your benefit for your corresponding status. For example, if you are 50K and select the bonus points as you benefit, you earn 50% of your base mile for your UA flight. (This benefit is not available for most other *A airlines, but specifically to UA and a few other AC partners)
5. Your SQM coefficient of service will be determined by the fare bucket you booked into (you can check here: https://www.aircanada.com/ca/en/aco/...artners.html#/ and select United). You can select the fare bucket you want to book into when you purchase UA ticket on their website (a bit tricky to find, but it is there).

I hope this answer your questions.

PS: if you book a ticket between a Canada and a US city, AC may issue a ticket with UA operated segment. In this case, the above points still apply. For example, your SQM coefficient of service for UA operated segment is NOT calculated according to AC fare brand, but UA fare bucket. Your access rule to the United Club is not related to MLL access rule, etc.