Those second motors have a much lower operating speed. The first ones absolutely need a large ratio reduction to be usable in a line follower. They're not going to be swapable.
The only trick to getting that technique to work is having wheels that are a little soft, about like a pencil eraser. Put them in and give it a try! They still might be too fast, 10,000-31,000RPM is quite high. See what 10% duty cycle will do.