Recording Mix on 2nd Sound Card, Separate From Traktor?

I recently got a new setup and will be mixing externally. The controller I'm using now has a soundcard with only outputs and no inputs. My laptop doesn't have any line or mic input. Would it be possible to have a separate usb soundcard to handle the input only? I'm thinking I would record using Audacity and the 2nd soundcard and use the 1st soundcard to handle the outputs for Traktor like usual. Would this cause instability or conflicts or should my computer be able to do both? I'm thinking I could use a basic Behringer U-control for the input recording.

You shouldn't have any issues, recording using a second interface isn't really all that processor intensive.

I hope you've got a fast HD - SSD ideally. Sometimes, you can get issues when you try to read & write at the same time...

I'm thinking about getting an SSD and putting it in the DVD drive slot of my laptop. Recording to a separate, faster drive than I'm playing off of should eliminate read/write speed issues right?

Yep, I have used a Behringer U-Control for a similar thing.

SSD's are a great upgrade but if you are getting primarily for for recording mixes perhaps look digital recorders.

Have a look at this: https://www.youtube.com/watch?v=J_PEn5chbK0

I was looking at recorders as an option too. It would be a convenient solution that wouldn't tax my laptop any more and would make it easy to record other people's set when we play shows together too. I wasn't finding any worthwhile options in a reasonable price range though, any suggestions?

I don't use them so can't really advise, your post just reminded me of that video.

Hope someone on here can give you a good recommendation.