While I haven't really used IPA for cleaning glass, I am sure it would work just fine. As for Eraser cleaning the glass before coating, I am pretty sure that Eraser comes in the FlyBy30 and Forte kits when you order them and is to be used as the last cleaning before coating. Not sure if this answered your question Mark.
Perhaps I could say both yes, and no. LOL
Although that seems like a good sign to me, I know Corey has once elaborated a bit about Carpro Eraser, and stated that it was designed basically to remove polishing oils after a polishing process has been done to paint, to remove oils from the products, but further stated that it was not designed to remove durable waxes and sealants.
So, with that being said, I am unsure with glass due to its nature just how well do such waxes-sealants and other coatings bond, and how hard are they to actually remove?
I would imagine in a high percentage of cases, that there may be nothing that would actually remove all prior products used, short of using perhaps a very harsh and dangerous chemical such as Acetone, which is an excellent glass cleaner, but extremely risky to use around Plastics, and Paint.
I know one Optician, and Telescope Manufacturer by the name of Roland Christen of Astro-Physics Telescopes, they make some of, if not the finest Refractor Lens Telescopes in the world, you'll be on a lengthy and long waiting list to get one. (I own one of their 4" Refractors called the Traveler)
I remember Roland once saying about chemicals such as Silicone, that to get Silicones on Glass Surfaces, nothing will remove it short of re-grinding, and re-figuring a Lens.
I then wonder how many products we may use upon glass surfaces that contain Silicones? Or, the contamination of the glass surface by waxes, or sealants used on paint that will over time find their way onto the Glass?
Mark