Nice showers Ron, yes working in condos is a challenge. And if you do good work the neighbors find out and you never get out of the building.
I like your niches that span the entire back wall.
Some pictures of the drain set up you are talking about would be good. Not sure if I completely understand it.
Most of the tub to shower conversions we do the drain location has to stay where the tub drain was because they don't allow us to chip the concrete to center the drain. It makes it challenging at times to get the correct slope and keep the perimeter level.
We usually time it so the drypack has time to cure and then we hydroban everything with fabric at changes of plane. If we don't have time for the drypack to cure enough for Hydroban we use Kerdi or Noble Seal on the shower floor and Hydroban on the walls and wrapping over the sheet membrane like in one of your pictures.
We have used-
Hydroban with a Hydroban drain.
Hydroban with a Kerdi Drain. I am loyal Laticrete fan but I like the Kerdi Drain better

The smaller size looks better in a typical shower and it is a great design.
Kerdi with a Kerdi Drain.
Noble Seal with a Kerdi Drain
One time we had a Hydroban drain installed but the schedule didn't allow for Hydroban so used Kerdi with it.

Sika Flex was used at the connection to the drain flange since there is no fleece on the Hydroban drain.
And sometimes the GC has a conventional clamping shower drain already installed so we do the divot method with Hydroban.