I believe a standard tub is 60". The drain is not at the very edge of the tub, probably 6-8" in. I think you will be fine. What is the space between the shower stub and the toilet stub? You need at least 15" of clearance between them.
My rough-ins were spaced too close together. I did not want to put my 2x4 wall too close to the foundation....I wanted to leave a gap so I didn't compress the insulation. I was left with only 10 1/2 inches between the wall and the center of the toilet flange. I was forced to use a 10" rough in toilet. I also wanted to use a 34"x48" shower base, but that only left 13 1/2 inches between the center of the toilet and the side wall for the shower. I ended up moving my shower drain over about 8 inches. It really wasn't that bad of a job except for my friend nicking a 3" pipe that was directly under the 2" shower drain pipe. I fixed that, but it gave me heart burn