Those lights only pull 6A when powered at 9V, your draw will be more like 4.5A at 12V.
Fuses go close to the power source (battery) and protect the entire circuit. Only one is needed per power leg, regardless of loads or switches in the circuit.
Either switch will work, but the fancier one will only carry 10A (vs 15A in the rocker). If you upgrade lights, you would need to use a relay switch or replace that switch to handle additional amperage.
That said, I would still probably use a relay to provide more direct power and remove the switch as a point of failure, though at that low amperage (<10A) it really is not required at all, as smaller gauge wire can easily handle that and run all over the place.
“Coming of age in a fascist police state will not be a barrel of fun for anybody, much less for people like me, who are not inclined to suffer Nazis gladly and feel only contempt for the cowardly flag-suckers who would gladly give up their outdated freedom to live for the mess of pottage they have been conned into believing will be freedom from fear.”