Hey Steve,
A few thoughts.
I think you're trying to accomplish a few different things.
#1 use the lopper with a mic
Although some loopers have an xlr input, if you have a looper without it, that can can be solved by using an adapter XLR to TS kike this:
https://www.sweetwater.com/store/search.php?s=xlr+to+ts+adapter
#2 transferring a file from the looper to your computer.
Some very basic loopers like the Ditto are easy to use but, have no capability to save or transfer files.
Typically the more advanced units have that capability at a higher price and with more complexity.
Good news...........
The new Ditto plus is a very basic looper but it adds the save and transfer capabilities
https://www.sweetwater.com/store/detail/DittoPls--tc-electronic-ditto-looper-pedal
So,
If you got a New Ditto Plus and an XLR adapter you'll end up with a simple looper that can work with a mic and transfer files to the computer.
I think the IMP unit will work, I suggest calling Sweetwater to variety that idea.