I have seen most of the tickets mention that 7kg is the Cabin Baggage Limit. But I often get confused whether it includes laptop bag weight also? Can I carry cabin bag and laptop bag both?
Typically, unless explicitly stated otherwise, assume the weight limit is the TOTAL of ALL items.
As to size, if it's larger than the maximum sizes mentioned, assume it's too large even if "it's normal for this kind of thing to be larger".
ACA doesn't seem to have a specific WEIGHT limit for carry on items, except that it must not be so heavy you can't lift it into the bins (which means, lift it over your head). That aside, I seriously doubt they're going to be happy if a professional weight lifter brings 100kg of carry on luggage, which he'd be quite capable of lifting :) Always keep in mind other passengers and that the bins have a maximum weight capacity, not just size. I've flown on flights where the overhead bins were stuffed over capacity and were visibly sagging. Not a comforting thought sitting under them, especially in turbulence.
Unfortunately, there are pretty much all variants. I have seen just in the last year the weight applied to the carry-on item only, the personal and carry-on item together and the personal and carry item each separately.
So it largely depends on the airline and the class of service. If unsure and you cannot find the info on the airline website clearly, then often you can contact support via online chat, messenger or phone. It will give you the official final answer, so you don't have to worry about someone giving you wrong or outdated information, or even the one for the wrong class of service.