If we could hear the sounds of these explosions directly where it was happening, how loud would each of these events be?
This is a kind of silly question because you are dealing with object (stars, etc) that cannot exist in an atmosphere so treat the whole below as a bit of a lark.
The decibel scale is logarithmic. 120 dB is one joule of sound energy. 130 Joules is ten times more: 10 Joules, 140 is 100 Joules etc. (Source)
The loudest sound on Earth is said to be Krakatoa at 180 dB. This is a megaJoule of sound energy. (source) But Krakatoa released 840 PetaJoules in total (source) or 840 billion MegaJoules. So 1/840000000000 of the energy was converted to sound.
If we suppose that the same fraction of a supernova's energy is converted to sound, and a supernova releases 1044 joules, That means that about 1044/(840 billion) = 1032 Joules of sound energy, thirty-two orders of magnitude greater than 120 dB, or about 440 decibels. This means that the sound energy would be enough to vaporise the Earth.
A kilonova is smaller, by a factor of 10 to 100, so 420 to 430 decibels, and a hypernova (really just a very large supernova) might be bigger by a factor of 10, so about 450 decibels.
These are all "silly numbers". You can't actually put that much energy into sound waves. So there is nothing "realistic" about this calculation.