As you have dismantled yourself so I will recommend you to get it checked from cng experts like Jilani cng etc. and get your cylinder removed too.
Kit with cylinder.. You can sell them to Jilani or others...
After removing cylinder, get your car cleaned from shops/guys near Jilani cng (Jail Chowrangi)
In 2500, your car will get better from exterior, interior and engine bay too.
BTW your central locking and power windows issues get solved or not yet, if not go to Kamran at Gulshan, he will give you Long life solution (I am Intentionally not writing PERMANENT SOLUTION)