MD-11 SAME RWY LNDG OVER SW-3 HOLDING IN POS. SYS ERROR. NMAC.

Narrative

VOLUME OF TFC ON FREQ WAS EXTREMELY HEAVY DUE TO SEVERAL POSITIONS NOT BEING OPENED; A SW-3 WAS POSITIONED ON RWY 35R WITH AN MD11 ON A 5 MI FINAL. CORRECT PHRASEOLOGY WAS NOT USED DUE TO WORKLOAD. SEVERAL MORE DISTRS OCCURRED AN ACR DEPARTED RWY 35L AND TAGGED UP ON THE WRONG CALL SIGN BECAUSE THE FLT PLAN TIMED OUT. I PROCEEDED TO COORDINATE AS REQUIRED WITH THE DEP CTLR TO ADVISE OF THE MISTAKE. THEY CALLED BACK 6 TIMES VERIFYING EVERYTHING. DUE TO A LACK OF A CAB COORDINATOR BEING OPENED; I DID EVERYTHING I THEN REALIZED THE SW-3 WAS STILL ON THE ARR RWY 35R AND THE MD11 ON 1/3 MI FINAL. I PROCEEDED TO ATTEMPT TO SEND THEM AROUND BUT USED THE WRONG CALL SIGN DUE TO THEIR TAG DROPPING OFF. THEY PROCEEDED TO LAND AROUND 1500 FT DOWN THE RWY UNAWARE OF THE EVENT. FAA MGMNT FAILED TO OPEN 2 CRITICAL POSITIONS; A RWY 31R CTLR TO WORK THOSE ARRS AND A COORDINATOR DUE TO THE LACK OF ROOM IN THE CTR TWR. ALL CTLR'S PROFICIENCY IS LACKING AT THIS FACILITY DUE TO ROTATING BTWN 3 TWRS AND THE VISUAL SCAN IS COMPLETELY DIFFERENT AND EQUIP PLACEMENT ALSO IN EACH TWR. PLTS NEED TO BE MORE AWARE OF THEIR SURROUNDINGS. MD11 NEVER HEARD ME PUT THIS AIRPLANE IN POS RIGHT AFTER I CLRED THEM TO LAND. WE NEED HELP TOO; WE'RE ONLY HUMAN.