You can draw an object on a frozen layer if you use a command icon in the tool palette. The layer associated wih the command will be thawed the time needed to use the command.
When you need to change all entities to the Bylayer color, you can use the LAYTRANS command, load the same drawing as the current drawing in the target field and click in the options to assign the layers to the same layers names in the target. This will convert all colors, even those in blocks, to Bylayer.
Did you know you can display buttons instead of icons on your status bar? Give it a try and right click the status bar...