before you waste any more money, please read the manual. The record decks should plug into the mixer, just set the switches to phono. The output goes to a power amplifier and then to the 'speakers, that's all you will need. [Shoot the people you bought all the unnecessary gear from].
To be honest, 'DJ' stuff is at the other end of the vinyl playing scale from most of us, that's not meant to be a derogatory comment, it's just that for most of us, quality matters more than other things which you may have as priorities.
kind regards, Cats
there are many churches, few are full.....