This is a must. However, various brands of adjustable sights are available, some better made than others. Again, experience will tell which one is better for you. Optical and electronic sights are available and are currently allowed in NRA Conventional Pistol competition. They are not recommended for the new shooter who is still mastering the fundamentals of sight alignment, which is absolutely necessary for a champion shooter.
All pistols come with grips.
Unfortunately, these are made for a standard size hand. Since no two peopele are identical, it is unlikely that the grips from the factory will fit properly. This can be as elaborate as a large box which holds everything to a simple cloth or leather case. The choice will depend on the type and amount of shooting you do. The box has an advantage as it can be used for storage at home.