A:AnswerYes, the camera has a very good incorporated mic; however if you're looking for a more professional or specific sound capture, you can get an additional external mic as an accessories to upgrade performance. For every day use, the internal mic will make a great job.
A:Answerit really depends on the capacity of the memory card and the your settings (you can make the camera take pictures on different sizes so they take less or more space)
but the system itself will tell you how many you can take
A:AnswerThe images in the owner's manuals (there's a basic one and a more comprehensive one) show an image that strongly suggests it is the old mini USB. The T7 is 5 years old, so it definitely won't have USB-C because Canon didn't start using USB-C until more recently. The manual says a cable is not included and never explicitly mentions the type. It always refers to the "digitial terminal" and the "interface cable". It does give model numbers of compatible cables, you could check Canon's site to see if it identifies which connector is used for the camera side: IFC-400PCU or IFC-200U or IFC-500U (the difference seems to only be the length of the cable). Searching for the first one, the first hit was amazon which showed a clear picture and also explicit identification: Mini USB. For such an old and low end camera, this really shouldn't be any surprise.