1. HD's in front will increase the ride stiffness over MD, and will maintain lift better if you have a heavy bumper or winch. I don't have either, but like the way the HD rides. It might keep the front leveled a little better with the HD's I have in the rear, I haven't tried the MD's so I can't say.
2. No, you don't need strut spacers, but you might want them.
3. You may be referring to camber bolts. I don't know what they are, I didn't need any. If you do, you can probably get them at your local alignment shop. Or, you can get them at 4x4parts.