Freehub body lubricant
 

I am servicing my freehub body. Can I use WD-40 to degrease it after removing the washer? Also, what lubricant oil can I use after to lubricate it?

I think you really need to provide more information. I know when I had my Mavic Ksyrium hub serviced that Mavic specify a very light oil but this is likely to be different for other manufacturers. Presumably there will be a service manual for your hub that will tell you what lubricant to use.

Ask the moderator to move the thread to thre mechanic's sub forum. There are serious mechanic there who don't waste their time here.

WD-40 will work to clean it, but is needlessly extravagant. Mineral spirits works just as well, and are both cheaper and reusable. Machine oil is adequate to re-lubricate. Freehub body bearings only move when unloaded, so no fancy lubricant is needed.