Re: T5i & USB Mic Question.
synching audio and video is always fun. depending on your software though it shouldn't be too hard. Like you said you need a visual action to match the audio - thats why hollywood uses clapper boards but your hands can suffice.
usb mics are great for recording to a computer but as far as I am aware nobody makes any kind of usb mic adapter.
you really have two options:
1 get an xlr adapter this will let you use most xlr mics and adjust the gain etc.
2 get a hotshoe video mic - this will be simpler but much less versatile
option 1 is more technical and expensive but will give you more options for different mics and better sound.
Re: T5i & USB Mic Question.
So that means looking one video camera better