Q8. "I desperately need information on what the constitution may or not say about capital punishment, and the use of it."
A. The Constitution does not address the subject directly. The 5th Amendment says:
No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the militia, when in actual service in time of war or public danger;...
The term "capital" varyingly means a crime punishable by death and a very serious crime (but, perhaps, not punishable by death). Here, the distinction is not very important (any court would likely take more liberal of the two). Basically, you can't be held unless indicted.
The 5th Amendment continues:
...nor be deprived of life, liberty, or property, without due process of law;...
In lay-man's terms, this means that you may not be executed, jailed, or have property taken or withheld without proper indictment, trial, and conviction. The 14th Amendment extends this restriction to the states.
The only other place the death penalty is (indirectly) dealt with is in the 8th Amendment — no cruel and unusual punishment. The definition of what is cruel and unusual is very flexible — what is cruel in our society is not in others; what is cruel now may not have been 50 years ago or 50 years from now. In 1972, most death penalties were thrown out by the Supreme Court en masse, though in 1976 the Court said that many death penalty laws, revised to come into line with the concerns expressed in the 1972 ruling, were constitutional. Today, constitutional challenges of the death penalty based on the premise that they are cruel and unusual don't win very often, and only rarely does the Supreme Court directly intervene in pending death warrants.