To access the delay interval of a scatterer instrument, first click on the scatter instrument to select it. Then, in the deck, if its “Trigger Behavior” drawer is not already expanded, expand it by clicking on the drawer’s disclosure triangle. Finally, click on the “Time” button to display the delay interval property.
As you have observed, when copying and pasting a transition marker with a transition timeline, automation on the transition timeline is not copied. However, you can copy the section of an automation curve inside a transition timeline by right-clicking on it and selecting “Copy” from the context menu, and then paste it inside another transition timeline. While not perfect, this method should at least save you from having to recreate the automation curve manually.