Hi Rich, Yes these discs will work for sanding drywall.
Hi Ken, Yes the Dewalt 6420 is a hook and loop sander and it will work with these discs. To attach, take the disc, align the holes on the disc with the holes on the sander and press it onto the sander. If you have any further questions, please call 800-334-4107 or email email@example.com. We're here to help!
If the Festool takes hook and loop and is 5" it should take it just fine. Also Festool probably has way better dust collection than mine and I prefer this to the regular aluminum oxide disks when it comes to that.
It does work on a hook and loop. It also comes with a supplemental pad if you need to convert yours.
Depends, if it feels almost like a velcro where the pad goes it takes a hook and loop pad. If it is smooth it takes an adhesive pad. You have to know what type your sander is and look at the packaging on the sanding discs.