Removing the RS lines from my bike for service.  They are internally routed through the frame and I have not looked yet, to see if the knuckle will fit without cutting the line?  And these are SRAM so I have to also think about the DOT hydraulic fluid spillage and splatter on the carbon and paint.

Aside from just cutting the lines and pulling through, any expert tips to share?

Thinking already of cutting the fingers off of Latex gloves and taping the on when I pull through with a fish line to not loose the channel.  (not not sure if latex will also get eaten by DOT)?

Any pointers would be appreciated from the experts...

Replacement and warranty service.

Replacing them with XTRs, (Yeay, mineral oil an more power!) lol

and sending these in for warranty service because they "failed".  Seen a lot of posts noting these are "problematic" with earlier revisions, so I guess I have those.  Lever got "spongy" and calipers started to drag after only a couple months...

Not sure if SRAMS policy is repair/rebuild or replacement?  They are only about 4 total months or so old with minimal miles.

If I recall, the last time I did a XTR bleed the lines remain "pressurized", so when disconnected, fluid doesn't blow everywhere.  Not sure if this is the same for SRAM?  Most concerned about getting the DOT fluid on things it will ruin especially pulling through the internal frame.

Nothing is under pressure unless your actively squeezing the lever.

Unscrew the compression nut from the lever body and pull the hose out. Some fluid will leak out. If you don't want to cut the lines, try to slip the olive off the hose. If the compression nut wasn't tightened down too hard, the olive may have not crimped very tightly to the hose. The barb could also be unscrewed from the end of the hose to make it easier. All of this only needs to be done to remove the compression nut from the line, so the line can be pulled through the frame. 

If you're worried about DOT fluid inside your frame (a valid concern), disconnect the line from the lever and caliper and let the fluid gravity drain from the line.

Not sure how latex holds up to DOT, but I know nitrile is resistant to it. 

As for SRAM's warranty service. In your case I'm sure it could be remedied under warranty (i think it is covered if within 1 year), but customers cannot directly contact SRAM for warranty claims. Warranty claims must go through an authorized Sram service center (bike shop). Best to not take anything apart yourself if you're trying to get it warrantied. Take it to a shop and let them diagnose it as needing warranty repair. If you bring them a box of pieces they will have no way to legitimately claim that it is a valid warranty claim (unless you have a good relationship with the shop and they are willing to vouch for your diagnosis.)

For all Avid/Sram brakes I have worked on, the hose barb actually is threaded and has a small torx socket in the end that goes into the lever body. Pretty clever actually. I prefer it over the Shimano system which is a classic push barb fitting. 

Honestly though, Guides and Shimano brakes are very similar in how they work. The only real difference is the fluid they use... well that and the fact that Sram f*ck*d up the tolerances on their plunger when they forgot to account for different coefficients of thermal expansion between different materials. The new plunger design seems to have fixed that though.

Good deal on the service center giving you the go ahead to take them apart. Just wanted to make sure you didn't get screwed out of a warranty.

My Carbine only has internal routing for the dropper.

If it were me, I would probably use an old brake hose or shift cable housing. Butt it up to the lever end of your current brake hose and tape them very carefully together with some gorilla tape (probably best to degrease both with alcohol first to ensure good adhesion). Then when you pull the old hose out, the dummy hose/housing takes it's place. Then remove tape, swap out old brake hose for new brake hose, re-tape, then carefully pull it back through.