What is the survival rate, with no stroke or brain side effect, of this procedure carotid endarterectomy?

Excellent. National statistical risk of stroke following carotid endarterectomy is quoted at 2-3%. If you have had stroke symptoms leading up to surgery, that risk doubles.
Depends on details. In general, experienced surgeons can perform endarterectomy with low complications. Many surgeons have a 2% peri operative rate of stroke, less than 1% risk of peri operative death. There is some risk to nerves that control the voice box but should an injury occur it is usually temporary. The key is to ask your surgeon what his personal complication rates are.