Mis-adjusted or damaged float can effect starting making it hard to start due to flooding. That would be why it starts sometimes and others not. Once you manage to dry the plugs from cranking it with the throttle open enough to spark it fires. Sounds like a float may be hanging up if it doesn't always do it. That starting could be ignition as an alternative (loose connection, etc..) but that still wouldn't make the carbs leak and the carbs leaking make me believe it has to do with that. Look at the needles and seats for damage or dirt, check the floats for fuel in them, and check for anywhere things are rubbing or not moving smoothly. You can check your float level by attaching a piece of clear tube to the bowl drain, hold that up along side the carb, open the drain, and the level in the tube will be what the level inside the bowl is. It should be slightly shy of the bowl/body joint.
