Money and the Constitution

Do I have any readers who are lawyers or who study law? (Or who are on friendly terms with a lawyer and would forward them this article?)

I have some monetary questions related to the United States Constitution, specifically about the gold standard. I quote Article 1, Section 10, and color-code the parts I believe are relevant:

No state shall enter into any treaty, alliance, or confederation; grant letters of marque and reprisal; coin money; emit bills of credit; make anything but gold and silver coin a tender in payment of debts; pass any bill of attainder, ex post facto law, or law impairing the obligation of contracts, or grant any title of nobility.

No state shall, without the consent of the Congress, lay any imposts or duties on imports or exports, except what may be absolutely necessary for executing its inspection laws: and the net produce of all duties and imposts, laid by any state on imports or exports, shall be for the use of the treasury of the United States; and all such laws shall be subject to the revision and control of the Congress.

No state shall, without the consent of Congress, lay any duty of tonnage, keep troops, or ships of war in time of peace, enter into any agreement or compact with another state, or with a foreign power, or engage in war, unless actually invaded, or in such imminent danger as will not admit of delay.

The purple text highlights the fact that the first paragraph, unlike the others, is absolute: The states are forbidden to do the things listed in the first paragraph whether Congress would permit them or not. The paragraphs are consecutive, so this must have been a deliberate decision; I cannot imagine this phrasing resulted from an editing oversight.

The blue text marks powers forbidden to the states, but explicitly granted to Congress by Article 1, Section 8.

The green text requires the states to adhere to a gold and/or silver monetary standard — but there's a slippery word here, "make". It clearly prohibits the states themselves from making anything but gold and silver legal tender, but today's Federal Reserve Notes are legal tender due to an act of Congress (31 U.S.C. §5103), not of the states.

My questions:

1. If the word "accept" had been used instead of "make", would the gold standard have been secure, at least on lands that are part of states?
2. The Constitution forbids the states to coin money, explicitly granting that power to the Congress. It also forbids legal tender power to the states except for gold and silver. Does the Constitution explicitly grant legal tender power to Congress? Where?
3. Anticipating an answer: If legal tender power is implicit in the power to coin money, why is the green text present at all? Does its inclusion suggest that these are separate powers and that one does not imply the other?
4. If Congress doesn't have legal tender power, but the states have the power to make (only) gold and silver legal tender, does this suggest that the only constitutional monetary system is based on gold and silver?