How much (if at all) will they interfere with the working of other satellites?
I mean, is it possible for its signals to collide with that of other working satellites?
No, radio signals can't collide with each other. Radio waves are made of photons, same as visible light, just at a different frequency. Take two flashlights into a dark room, and shine them so that their beams cross. There's no interference, the two beams strike the wall with the same intensity that they would have had if the other flashlight wasn't there.
The only way these satellites could interfere with another is if they happened to line up between a satellite and a ground station, such that the ground station's antenna was picking up both satellites. But the fact is that satellites move so fast that it would be in an out of the field of view of the antenna in milliseconds, if not less. The end result is that the antenna picks up a tiny burst of radio noise from the other satellite, and since that kind of thing happens all the time anyway, the ground equipment could just correct for it without even knowing another satellite was the cause.