I've had to cut several holes in my plaster board walls in order to make plumbing and wiring improvements. I've chisled the plaster out, but the cuts aren't clean as the rockboard has peeled away somewhat behind the surface of the wall.

I'd like to patch this up this weekend, but I'm not sure what the best way is. I'm thinking of going with drywall cut to the hole shape and then building it up to be flush with the wall. The plaster board is about 3/4" thick, so I was thinking of using 5/8" drywall. Is this the best way to patch the holes?

My ceiling in the hall is textured with a slight stipple. Can I re-create this with a layer of joint compound and a wet sponge? Do I need to clean up the edges of the plaster, or is it better to leave it the way it is and try to fill it with joint compound? If I should clean up the edges, what's the best way to do it (with as little dust as possible)?

Thanks