Did you try highlighting the fighter portrait in the bottom left or bottom right corner? The DLC fighters should appear when you highlight the bottom corner portraits.

I found this on another forum. Hope it works:

And as for a glitch pertaining to some DLC characters not appearing, if you bought them in MK9 they will sometimes not appear for you in MKKE. For instance, say you bought Rain back in July, but now he isn't appearing on MKKE. Or in my case, I never bought Freddy but he still wouldn't appear on my console. You need to go to your system settings and delete all DLC. Yes, even if you can see Skarlet, Kenshi, and Freddy, you need to delete them all just to be able to select Rain. They will all be there contrary to the deletion of their saved files in the MK9 saved data storage. If your first experience with the newest Mortal Kombat is through MKKE however, then you will have no problem.

wait your roommate took off with ur mk wtf????

Ive tried going down to Cyber Sub-Zero and I try to move the cursor to the left and nothing happens

When I had the orginal MK I didnt have Xbox Live so I never downloaded any dlc and I even tried it with another profile that has no MK save data and it still doesnt allow me to select any of the dlc characters :(

Ok I finally got them to show up by going and deleting the Skarlet Kenshi Rain and Freddy marketplace content under the MK saved data storage even though there was no reason for there to be any marketplace content since I never downloaded them or the fact that a brand new gamer profile with no MK save data didnt have the 4 accessible either but anyways Im finally able to select the 4 of them so now its finally time to enjoy MK Komplete edition

Delete All your mk9 info.. gameplay, network and misc related mk9 stuff before using komplete