The E drain will become a siphon if ever the main one clogg. It will be the same pipe setup, just a bit above the first drain..I dont know where you read that. The stand pipe is just the pipe on the overflow so essentially both durso and the siphon are stand pipes.
This stuff can be confusing
The siphon line will be silent. Much more quieter than a durso and it will move more water. In your set up the durso isnt needed. The e drain is a gravity fed line (non siphon) this is the most important part of the planning because with out it there is not safety factor. 1 inches wont handle 1700 gph