I'll just answer the points I know about, as I suspect some others may vary from aircraft to aircraft.
1. No, you do not reduce tyre pressure. There is no need to do so as the difference between seal level and cruise is only about 10 psi and you can get bigger differences in pressure operating between cold and hot airports. There is no mechanism to adjust tyre pressure in flight, up or down. Set the pressure cold before departure, don't bleed off if hot. No further adjustment.
2. Many aircraft have snubber strips in the NLG bay. More than anything else this is to stop the nosewheels rattling the pilots' fillings. They sit directly on top of the gear and any vibration or shimmy is felt by them. On some aircraft types nosewheel vibration is a major cause of wheel rejections even though the tyres are not worn to limits. Mainwheel vibration is not felt by the crew so I doubt there is a pressing need to brake the main wheels, and as Guppy indicated you don't want to risk landing with brakes applied. Depends on your ops manual I guess.