Any tricks to disassembling an Easton R4 rear hub?
Yes, this is a horrible hub due tot he cone shaped pieces you are hammering on. You need to go to the shop and buy one 19mm (I believe) cone wrench. It'll solve everything. Also, buy another set of these cone pieces as they are what adjust the bearing tension (they are sealed bearings) and you have likely damaged them.

If there is no indentation for a cone wrench, which was the case on mine, I used a rubber mallet and taped at the cones obliquely as possible till they were off. The new ones will have the cones wrench fitting. 

Easton had a problem with these cones coming loose. The way that mechanics handled it was to use loctite, which held them in place but made it insanely hard to remove without that oversized cone wrench. The new cones you'll buy are the updates and will hold on their own. 

While your at it, be sure to clean the pawls thoroughly and use a thick oil, like gear oil, or marine grease to lube. And pick up a new seal so it won't let water in.

That is what the problem is. I destroyed the cone pieces in the end, cleaned the threads on the hub, lubed them with light grease and put them together. Customer is still using them years later.  Good luck!