a. I treated many of my lines with water repellant made for climbing ropes. It replaces the spinning lubes and stopped all of the squeaking under load, even in an ancient mainsheet. By reducing internal abrasion, it extends the life of older lines. Also, the product goes a LOT further than the label says; just keep using what's left in the bucket for more lines.
Wash in waterproofing for rope | Rope Proof
In some ways it is like fabric softener, but many
times more effective and longer lasting. Hey, it MADE for ropes.
b. Tubular webbing makes cheap, long-lasting, quiet, and non-water proof chafe gear. I've used this for 25 years. $0.68/foot. The small 1" webbing works for lines 7/16" and smaller.
BlueWater 2" Climb-Spec Tubular Webbing - Free Shipping at REI.com