Merc do provide a primer bulb with new Optis. I fitted one to mine, but have never had to use it!
Opinion is divided on the bulb position, relative to the filter. Some prefer having the bulb before the filter, which effectively pushes the fuel into the filter. This makes sense, as there is no impediment/restriction between the fuel tank and the bulb, BUT, the instructions which came with my Racor filter said to put the bulb after the filter unit.
Filter is safe, but more vulnerable, positioned on the transom. It will last longer inside the console though. Keep it separate from your battery.