How do I Preload grapgics for the Layout

Is there a way, short of placing an instance of it offscreen , to preload graphics for a layout that could be created?

(they make sounds I don't want going off at the start)

sometimes when my character uses a new skill or some explosions pop up there is a small drop on framerate each time a new layout has to load them up.

Nope, you need to have it on the layout that's currently in-use. Quick fix to your audio on spawn issue: run that event with the condition Sprite/family/etc: is on-screen.