Q: What is the best way to create a drawing with my light fixtures or diffusers that I can send to the architect for his reflected ceiling plan?

A: Use the Copy Drawing and Remove Links to Database command.

Ribbon: DM->Utilities->  ->Copy Drawing and Remove Links to Database

Pulldown Menu: DM->Utilities->Copy Drawing and Remove Links to Database

Erase everything from the drawing except for the light fixtures or diffusers you want to send to the architect.

The copy command creates an exact copy of the drawing that is not connected to the project database. Deleting devices from the drawing will not remove them from the database. You are free to make all of the changes necessary for the drawing you want to send to the architect without having to worry about what will happen to your database.