I have trapped water with Eternabond in the past. It was my fault, and even though it had been there for years there was no damage. If you're laying the tape down on flat surface and not trying to be creative, it work just fine. The main thing about it is that it lasts for years and years. The caulks you mentioned are good, but they will crack over time. A combination of the three isn't a bad thing. I laid Eternabond over some self leveling sealant, then added sealant to the wrinkled edges of the tape just to be sure. It's worked great for years that way. Later, I covered the entire shebang with Heng's roof coating. Now it's nice and uniform and so far still looks good though it's only been about 18 months.
One awesome thing about the roof coating was how much cooler it stayed inside. The old rubber roof was getting pretty black.
