1- the 3 nz.exe is not meant that nz is unpacking 3 files at the same time
this means it uses 3 threads to unpack one file
2- to use 3 nanozip at the same time you must have a good pc 'cause I see from the pic 1 nz is talking around 75% of your cpu so 3 will extremely crash your pc or making it stuck !! uless you change nz settings in arc.ini to use only one thread so you can use at the same time 3 nanozip for 3 files
3- For inno I don't know