Highly unlikely.
No, a bad coil will not drain the battery.
If it stays on all the time it will drain the battery
there is a short some where in the electrical system... or a bad battery.
bad ignition switch, bad battery, bad alternator/regulator,
Your alternator could be bad.
No, it can cause you to use and excesive amount of fuel but it will not effect the battery.
Bad Battery. Bad Alternator. Lights left on by mistake. Something left running. Exc.
Could be a shorted wire, or bad battery.
Your starter is incapable of being drained. It is an electric motor. However a bad starter can drain your battery
Bad battery or a parasitic drain
Good possibility
Yes