16 mm COMMAG cameras, combined magnetic sound system, are professional gear. Today you can find those cameras for cheap but prestriped stock is no longer available.
You can have magnetic stripes on processed film, also polyester base, at Vangelisti, Italy. So if you want to work with a COMMAG projector, you can go that way, rerecording until satisfactory. 16 mm sound production is expensive. Sound recorders are no longer bulky and heavy but you still have to take care of camera noise dampening, directional microphones, crystal control of the camera motor, and claps. After the shoot you either synch and edit copies on an editor or, more expensive still, with an editing suite. You can try to edit image and sound digitally yourself but then you have left filmmaking.
If it’s not entirely out of the question, shoot 8 mm. You can pick a projector-coupler-recorder combination that will perform like nothing available in 16 mm. You can use relatively cheap magnetic tape, copy recordings, and cut those up. Or record digitally, copy onto tape, and edit. Sound couplers work with smooth rollers or sprocket rollers. Higher tape speeds can be combined with modest frame rates such as 16 fps and 7.5 ips (19,05 cm/s). Perforated magnetic stock is made by Pyral-Mulann, France.
If you are crazy enough, find a 16 mm optical sound recorder. Feed it with ORWO TF 12, develop the recordings. Have prints made off the sound negatives. Now you can see the sound and edit on viewer and projector.