path tool question

Any object you draw can be made turned into a Guide. Draw an object and with it selected go Menu>View>Guides>Make Guides. The object is now a guide. The color of Guides can be set in Menu>Illustrator>Preferences>Guides and Grids… Isolating guides onto their own layer is a good idea and you can even use these objects later in the artwork if need be by releasing them from being guides or copying them and releasing them form guides. The good thing about having objects as guides is you can snap to them or lock them, show or hide them. Use the same View>Guides menu to do these functions.

This is not a direct answer to your question, but have you considered using "Shape Builder" or "Live Paint" tools to generate the desired shape(s) directly, by duplicating your guidelines?

If the template image is on its own layer, you can lock that layer to prevent the pen tool from connecting to those paths, but it will still snap to the points if Smart Guides are turned on. If you want to keep Smart Guides on for the current layer, but prevent any interaction with underlying layers, you can make a copy of the image on a new layer and rasterize it with Object > Rasterize. Then turn off the visibility of the vector version.

But that might prove counter-productive, since snapping is a good way to ensure precision and accuracy of angles and point placement. I can see already your green lines aren't parallel to the black shape underneath.