As the statutes differ from state-to-state there is no certain generallized answer to this question.
If the conspiracy came to fruition, you could be charged as a principle in the offense, a felony. If the robbery never took place, possibly a misdemeanor.
Attempt means that the action has been attempted, but not completed. Such as attempted murder. You injure someone or you have the undeniable intent to kill them or hurt them to such a great extent as to be near death or inflict great bodily injury, but they live. Conspiracy is like conspiracy to commit murder--individual(s) plan to commit murder, or are suspected of planning to commit the crime of murder. There are many different aspects that may need to be taken into account before the crime of Conspiracy can be charged, for specific Conspiracy charges.
Robbery sentencing depends on the amount of money taken and the manner in which it was taken.
Depends on the law where you live. In many areass, the max is life in prison with no parole, or execution.
5 to 10 years
Common motivations for robbery include financial need or desperation, substance abuse or addiction, peer pressure or influence from criminal networks, and a desire for material goods or wealth. Robbers may also engage in the crime to exert power or control over others.
25-30 years prison
The sentence for conspiracy is often different comparing various nations and Governments. Also, the sentence for conspiracy to fraud is quite different than conspiracy to kill. If a person conspires to deal drugs to others, the sentence would be if he or she committed the crime in Indonesia, jail for many years, with daily floggings, real whips daily on the back. If a person conspires to kill many people, it could be in some nations: jail for the rest of the natural life (just sit in jail until you die), or jail for 14 years at least. For some people found guilty of conspiracy, they are also fined all of their own bank funds, and for some people its' the death penalty. If a person is found Guilty of war-crimes, the death-toll is added up and the person goes to jail for even the rest of their natural life, like some of the Nazis did under the War Crimes investigations.
Too many. This is especially common in the children of parents who commit suicide. The children may not commit suicide for many years but there is a definite increase in the risk.
Depends on the law where you are. In some circumstances, life in prison.
life
Over the years there have been many. You might be thinking of "Dog Day Afternoon."
A Conspiracy of Paper has 448 pages.