Thanks to @DavidMaze I solve it. It was just a matter of deleting the strings and posting them as actual paths and the script did why I wanted. (stop running once I closed all the apps)

Thank you also to @furas to simplifying my code it runs much faster.

Final solution:

import os 
import sys 
import subprocess 
from subprocess import Popen

def back_insert(filename):
    #inserts backslashes into paths that have spaces in them
    fstring = filename.replace(" ", "\\ ")
    
    return fstring


#Runs the Emulator, socket, Timer and Tracker
commands = [
back_insert("/usr/bin/snes9x-gtk"), 
back_insert("/usr/share/OpenTracker/OpenTracker"), 
back_insert("/usr/bin/QUsb2Snes"), 
back_insert("/home/user/LibreSplit/libresplit")
]

procs = [Popen(i) for i in commands]
for p in procs:
    p.wait()