When all doors are closed, you hear a beep - the car is telling you all the doors are closed properly. Walking away from the car, you hear another beep - and this signifies that the car is locked. You can also manually lock it by touching on the stripped bump on top of the handle of the driver&passenger door handle.

This will be difficult. Especially as such providers rely on making profits off the products they use and not just charging for services. I would advice you forget about approaching the big/well-known brands as those have reps to protect and won't want to be liable, should your product screw up your car's paint or body. Try those smaller mom & pop type shops. Might bump into an employee looking for quick cash. Of course, zero warranty and guarantee on the end result.