While I do lust after a BGE, I have to take issue with the above..... you are just describing the difference between lump and briquettes which applies the same to an egg or a kettle grill.
If you use lump with a kettle, which I fully recommend for all the same reasons you list - and also because it burns hotter, then you get the same low ash and easy lighting. Then just shut the vents on the kettle after cooking and the unused lump goes out to be reused the next time. I am sure that an egg does use less charcoal than a kettle though.
I would also recommend the use of a chimney starter for charcoal rather than firelighters due to the chemicals in them. A single sheet of newspaper, one match and the charcoal is ready to cook in 15 minutes.
In regards to the BGE, lump is the only fuel recommended. No matter what type of charcoal used in the kettle, you still use much more charcoal than a ceramic grill which is more efficient. More fuel used = more ash....even lump. I am surprised you have lump or briquettes remaining after cooking on a kettle? I very rarely did, even after shutting the vents completely down. This was mostly due to the poor insulating properties of porcelain enameled steel and the lack of tight seals with the lid and vents on the base. On the egg shutdown, the fire is starved of O2 immediately. The heated ceramic takes hours to cool, but the fire is out.
I agree that a Weber brand chimney starter is a must with a kettle. A waste for the BGE. A firestarter dropped into the middle of the charcoal works just fine with the updraft. I first started using newspaper in the chimney. The burnt newspaper gets easily caught in the wind and blown over your cooking area. It also has a short burn time. A paper towel tied in a knot with a small drizzle of used cooking oil works great and there is no burnt newspaper flying around. Another option is using wadded up pieces of the charcoal bag, same results, no flying ash. The firestarters are not an issue when used properly. They completely burn off in the preheat, doing no harm.