Re: "Silent" Ukemi
I don't know if you have seen the yoshinkan style of break fall/roll, this may be one to try. I 've seen some very experienced uke's take ukemi by placing the hand down in a breakfall and then allowing the rest of the body to settle. sorry poor description i must admit it look much smoother and less impact than the judo style. However i am still undecided a hard slap with the hand does allow the body to settle comfortably too and allow for quickly regaining footing.
In forward roll i believe any impact is noise therfore sending forces through the body so from that point softer could be better. Relaxation is the key there.
Also the core strength is very important, Pilate's type exercises definitely help.