Regarding the attack, confirm the value, orientation and soldering of C8, P1 and R5. Other than that, I am not sure why the attack is not to your liking.
If you have unity level at about 50% rotation of the VOL pot, that is very typical of many pedals. Most designs are not intended to dime the VOL in order to reach unity.
Undesired hum or noise when the strings are not being touched is usually a matter of poor shielding of pickups, cables or pedal enclosure. Look for a poor ground connection. Re-soldering may disclose a bad joint. Try installing those 3 ceramic caps even if you do not have the exact values.