My car has felt lose for the last week or two. I'm fairly certain the tie rod ends need replaced. Can I put new TRE's on it and have it aligned then put the fronts on the back and backs up front? Or will the be worn out of alignment and be worthless?

(meaning I will have to by new tires for the front, rather than just rotating them, they are at about 50% left and I cant tell a bad wear pattern)

 

if your alignment is off then the tire will wear unevenly............when it wears unevenly the wheel and tire becomes unbalanced, so you putting them on the rear will not help anything.

I suggest just getting new tires IF they are worn to where you can see a difference.

If you cant tell a bad wear pattern then put them on the new wheels and see what happens. FYI vibrations can not only be caused my alignment problems (brakes that are rubbing unevenly compared to each other can cause it)