Does the file extension matter?
What if I extract the VeraCrypt hash (.vc) into .tc file or maybe into another extension? Will this play a role in a successful attack? 
I use:
 sudo dd if=/dev/disk2s1 bs=512 count=1

Could filename be with a different extension? Does it matter for hashcat when I start an attack -m 13721 on a
no, it doesn't matter. hashcat will still crack the hash independent from the file extension.

but let's be honest, it always makes sense to use something meaningful and clever to avoid confusion later on etc.