Reply to S4 and CDJs

Whats up guys I am new to the world of mixing and am believeing of buying my first setup after playing around on my friends controller for a few months.

Like many people im stuck between wanting to use the cdj/mixer setup and a controller/software with my laptop. I want to begin to become comfortable with both but money is of course an issue and I cannot afford to buy all the gear I would like.

So heres my question: If i decided to buy an S4 to use with traktor along with a pair of cheaper cdjs that may not be midi enabled, would I be able to use the S4 and the traktor software as a mixer for the cdjs? I wouldnt need the cdjs to control traktor or anything, just the controller and software to act as a mixer for the audio output from the cdjs. This would be great for me as a beginner as it would allow me to become comfortable on more diverse gear without having to shell out for an expensive mixer and expensive midi enabled cdjs ontop of a controller. At least until my skill level improves enough to justify the purchase.

Additionally, if this is indeed possible, as the S4 is 4 channel would I then be able to mix the cdjs at the same time as using the other 2 channels on the controller to control traktor normally?

Thanks in advance for any answers and please let me know if you believe I am not understanding any concepts correctly.