Space Elevator
To take advantage of the planet's rotation, the base of the space elevator must be placed at or close to the planet's equator.
Geostationary Altitude (cable disembarkation height) = $^3\sqrt{{GM}\over{\omega^2}}$
= 48,938 km around a world of 70% Earth's mass, with a 36-hour day.
The top of the elevator depends on a lot of design decisions. In most literature I've looked at, $r_{end}$ is between 2x and 4x $r_1$ Therefore, the top of the elevator is somewhere between 96 thousand and 200 thousand kilometers.
Interference:
Anything with a precessing orbit < $r_{end}$ will eventually become a collision hazard. However, as long as these are controlled craft, you can plan ahead and adjust your path to avoid the cable.
There will be ongoing "air traffic control" around the cable to monitor for hazards.
Feasibility:
The tension in the elevator cable (if made of Zylon at a density of 1,700 kg/m^3) is in the neighborhood of 100 to 400 gigaPascals (GPa). Currently, the strongest industrially available materials are much weaker than that (Zylon itself is about 6 GPa)
Orbital Ring
A planetary ring makes a complete circle around the planet at low altitude (usually less than 100 km). It is, by definition, stationary relative to the ground. In most designs, the ring is kept in place by tethers that keep the ring centered around the planet.
Because the ring is stationary, it can be pre-planned that the path of the orbital ring does not interfere with the space elevator. The orbital ring does not have to be positioned on the equator, but it must have the planet at it's center (so no offset polar ring at 70 degrees N latitude)
Feasibility:
The compressive strength required for this construct is comparable to the space elevator in the range of a few hundred gigaPascals (~ 587 GPa for a steel ring).
This is still beyond the range of currently known materials by a few orders of magnitude.
Skyhook
A skyhook is a heavy space station (maybe an asteroid moved into position), that lowers and raises a cable that ground operators can connect a load to at various points on the planet surface where the space station overflies.
Alternatively, the skyhook can be designed for loads to be hooked up in mid-air. The skyhook will then lift the airborne load into orbit.
It requires a lot of energy keeping the station in place, but the skyhook has been proven possible with existing, or nearly existing technology. There have been a few designs demonstrating the feasibility and materials used.
Interference:
If the orbit of the station precesses, a sky hook will become a predictable hazard for a space elevator. The elevator can be avoided by correcting the position of the heavy station. And how often the problem comes up can be done by selecting an orbit that rarely or never intersects the elevator.
A skyhook basically does what an orbital ring or space elevator do, but at a much higher operational cost. I'd imagine sky hooks would be a legacy technology in any civilization that has space elevators/orbital rings.
Skyhooks might still fit a niche for dangerous loads you don't want on the orbital ring/elevator. Or private loads that you'd like to have picked up where you are, instead of hauling the load to a ring/elevator ground station.
