2013 3.0 TDI - Probable EGR Valve coolant leak

I had to add one quart of coolant to the reservoir this weekend. I was backing up out of garage, low coolant warning came on the display, and yes, sure enough, the reservoir was low. Just about at the minimum marked level. I could clearly see the sensor electrodes.

This was the SECOND time since late December 2017. I also had the identical same thing happen. First engine start of the day, backing out of garage, and light came on. The first time it happened on a late December Saturday morning, I drove to VW dealership and bought $27 gallon of coolant. Added almost exactly a quart then too.

I looked for a leak under the Touareg, but nothing. No wet stains whatsoever. I had NEVER had an issue in almost 5 years, so I thought MAYBE evaporation?? Although with the 10K dealer performed service intervals, I always expected that they would catch and fill coolant if needed. Now that this is the SECOND 1-quart fill in exactly 6 weeks, I am bothered. The last 10K was in November, and I was into the service area in early December for the emissions-compliant repair. They did change out one glow plug, no reason given, during the emissions repair.

Reading the thread makes me think it's an EGR unit leaking coolant into the exhaust. I see no oil contamination in the reservoir, so it's not likely to be a head gasket.

I HAVE NOTICED in the last few weeks on cold mornings during acceleration I see a large white cloud on occasion. I usually never noticed anything before. I was chalking it up to the cold mornings and water vapor but now I think it's a bit of coolant blowing out the exhaust.

I'll be calling the dealership tomorrow, to take it in for diagnostics. Extended platinum warranty in force, $100 deductible, thank goodness.

QUESTIONS:

1) Would a coolant system pressure test reveal a leaking EGR valve?
2) Any other possible areas where losing 1 quart over 6 weeks could go unnoticed, water pump, etc, anywhere? As I said before, NO visible leaks on the garage floor so I think it's heading out the tailpipe.
3) IF it is the EGR valve, could this also cause other possible problems "down the line". DPF filter blockage/failure, Catalytic Converter poisoning, turbocharger failure??? I would be pissed if this caused some damage not diagnosed now, and later out of warranty "became" an issue.