I had one of those Redhawks and it used the moonclips. But if I recall they had to be the thin ones. If you got thick ones they were too thick. I found one company that had some that would work. I can't recall what their name was.
I doubt it. The outfits I'm familiar with for moonclips (TK custom is the best, but there are others on Amazon, etc.) list separate clips for S&W 25/625 and the Redhawk.
I have a Redhawk that was converted to use moons before the factory built one. I use "Ranch Products" moons for both my Redhawk & my S&W, interchangeably.