There is a microswitch fitted to the clutch lever that tells the bike that clutch is pulled in and it's safe to start. That switch has probably failed, or the wires to it disconnected. It might also be the side stand switch. You can temporarily bypass this by shorting together the wires going to it.
For the horn, check the wiring as it passes over the lower fork yolk. It often rubs through the insulation there, and as you move the bars bare wire shorts to ground on the top of the yolk, taking out the fuse. Wrap some tape around the wires at that point and if possible, use a ty-wrap to lift the wires clear of the yolk.