No
You do not have to have blinkers on a motorcycle in Texas. If you do have blinkers they have to work properly. But if you DO NOT have blinkers you can still get the bike inspected and you will have to use hand signals or risk getting pulled over for not using hand signals.
Yes, it is legal to use hand signals when driving. In fact if your turn signal goes out you should use hand signals.
No, turn signals are required on the vehicle.
yes
Hand signals are to this day a legal form of traffic control devices.
If you don't have turn signal lights then you must use hand signals.
technical foul,e legal dribbling
Make sure the wires to the blinkers are not loose and that the bulbs work (turn on the hazard lights to see). It is best to call a mechanic to look at your vehicle. While some places do allow you to drive using hand signals, some countries do not allow it. Since you didn't mention a country, we cannot advise you legal-wise.
Yes
Yes, but you also must have operating turn signal lights.
Yes, it is legal. Watch out though. Anything other then open hand on the buttucks that leaves no marks can get you in trouble.
Turn signals are definitely preferred. Most drivers don't look for hand signals, but, they do look for turn signals. Some people don't even know how to make correct hand signals while driving.