In particular, there are a limited number of geosynchronous slots
Really? That's a circle of about 43,000 km radius, so more than 170,000 km long. Even if you want certain points, it's not like it's packed over there. You can separate a satellite some km from the next and still have plenty of space for hundreds. If a satellite is at the same distance from Earth as others, they won't be moving relative to them.
Really! The orbit of a satellite is not perfectly stable because of the effects of the solar wind, the gravitational lumpiness of the earth, etc. IIRC the slot for a satellite is about 300 mi. wide. There are preferred slots such as over Europe or the east coast of the US with lots of countries contending for them, and slots allocated to countries that don't yet have satellites.
Really? That's a circle of about 43,000 km radius, so more than 170,000 km long. Even if you want certain points, it's not like it's packed over there. You can separate a satellite some km from the next and still have plenty of space for hundreds. If a satellite is at the same distance from Earth as others, they won't be moving relative to them.