No to both questions. But...you can still get the end result, just in a different way.
For the loop, you'll have to duplicate the clip over and over until it reaches 1 minute. Easily done with keyboard shortcuts for Copy and a whole bunch of Pastes.
For replacing that many clips, it's easier to do this outside of PP. Close the project, rename sound effect A on the hard drive to something else, and then rename sound effect B to sound effect A. When you reopen PP, it will think effect B is effect A because it has that name, and all sound effect A clips will be using effect B. Take note that this process will affect all A clips in the entire project, not just one sequence. If you want to do this for just one sequence, or if you still need to use effect A somewhere else, then you'll need to do things the hard way by replacing every clip you want changed manually.
yes to the second question,
if only copies of this one sound effect A are in track 1, just lasso them all, if not, shift-select them all.
then alt-drag effect B on them and it will change all selected A clips to effect B.
you might have to nudge them all together a bit for the right timing afterwards, since PR takes the in- and out points from the original edit, just like AE.
Thank you for your advice. By the way, I tried the way Felix said, and dragged and dropped the files, but something is strange. For example track a has those 3 sound, like this.
track A (soundA) (soundA) (soundA)
And I drop soundB and all soundA is replaced with B at once.
track A (soundB) (soundB) (soundB)
I tried to play the clip, first soundB has sound, but after that there is no sound, second and third soundB has no sound. I checked both sound wave, and there is nothing. Is it correct? I need to do something to fix both?