1)The Pittman Act of 1918 resulted in the melting of over 270 million silver dollars. The bullion was sold to Great Britain for use in India where Germany used a propaganda campaign to undermine the value of silver certificates. Mass redemption by Indian citizens caused a severe shortage of silver that served to back the currency. This action occurred in the midst of WWI and Germany was trying to break the British economy through indirect actions in India. The silver from the US served to prop up the currency so India did not revolt against British rule. After WWI, the US planned a new issuance of silver certificates in 1923 and since the previous stockpile was gone, new silver dollars were needed for the backing of US currency and the Pittman Act also specified that replacements be minted.
2)Public Law 88-36 of 1963 provided that "Silver certificates shall be exchangeable on demand at the Treasury of the United States for silver dollars or at the option of the Secretary of Treasury, at such places as he may designate, for silver bullion at a monetary value equal to the face value of the certificates." This law helped to end the usage of silver certificates in commerce as they were withdrawn from circulation when redeemed for silver dollars. Legislation, sponsored by Senators from Western mining states, was passed on August 3,1964 which authorized the minting of 45 million silver dollars utilizing the old Peace design. At the time, silver was being rapidly pulled from circulation which resulted in a coin shortage so there was not enough capacity to mint a denomination which had not seen extensive circulation in several decades. Once the sponsoring Senators realized the complications of their aspirations, they recommended to the Treasury that minting be stopped. However, a total of 316,076 Peace dollars had been minted at Denver before the original order was reversed on May 24, 1965.
3)By 1928, the 270 million replacements authorized under the Pittman Act had been minted. The Thomas Amendment to the Agricultural Adjustment Act approved May 12, 1933 authorized acceptance of silver on war debts for a total amount not to exceed $200,000,000. The law also authorized that accepted silver be converted into silver dollars and minor silver coinage. All of this silver was exhausted by 1935 so no more Peace dollars were minted.
4)The Eisenhower dollar was issued in 1971 as a dual tribute to recognize the death of Eisenhower and the Apollo Moon Landing which both occurred in 1969. Convenience of use was an afterthought and the size proved to be its eventual undoing. In 1979, it was replaced by the ill-fated "Carter Quarter", possibly the single worst idea in US coinage history. At the very least, a close second to the 20 cent denomination.
5)Due to the rising use of dollar coins in vending machines and mass transit systems in the 1990s, Treasury stockpiles were dwindling. The Sacagawea dollar was was authorized under the United States Dollar Coin Act of 1997 but Treasury officials feared that supplies of dollar coins would run out before minting of the new golden dollars was to begin in 2000. In order to meet need, a short run of ~41 million SBAs were cranked out in late 1999. So late in fact that the 1999 proof was not included in the regular proof set, it had to be sold individually.
6)The Presidential $1 Coin Act did not replace the Sacagawea series, it was only written to be a primary supplemental series and also decreed that 1/3 of the total dollar mintage be Sacagaweas. The Native American $1 Coin Acta replacement for the Sacagawea series, did little to alleviate the duplication problem but the mintage requirement was reduced to 1/5.
sources: Comprehensive Catalog and Encyclopedia Of Morgan and Peace Dollars and A Guide Book of United States Coins
As you pointed out, confusion was a popular theme but it did not stem from the Mint itself. Actions by the Mint are strictly dictated by Congress and various political maneuverings and machinations were responsible for the confusion and contradictions throughout the years and it still continues to this day.
2)Public Law 88-36 of 1963 provided that "Silver certificates shall be exchangeable on demand at the Treasury of the United States for silver dollars or at the option of the Secretary of Treasury, at such places as he may designate, for silver bullion at a monetary value equal to the face value of the certificates." This law helped to end the usage of silver certificates in commerce as they were withdrawn from circulation when redeemed for silver dollars. Legislation, sponsored by Senators from Western mining states, was passed on August 3,1964 which authorized the minting of 45 million silver dollars utilizing the old Peace design. At the time, silver was being rapidly pulled from circulation which resulted in a coin shortage so there was not enough capacity to mint a denomination which had not seen extensive circulation in several decades. Once the sponsoring Senators realized the complications of their aspirations, they recommended to the Treasury that minting be stopped. However, a total of 316,076 Peace dollars had been minted at Denver before the original order was reversed on May 24, 1965.
3)By 1928, the 270 million replacements authorized under the Pittman Act had been minted. The Thomas Amendment to the Agricultural Adjustment Act approved May 12, 1933 authorized acceptance of silver on war debts for a total amount not to exceed $200,000,000. The law also authorized that accepted silver be converted into silver dollars and minor silver coinage. All of this silver was exhausted by 1935 so no more Peace dollars were minted.
4)The Eisenhower dollar was issued in 1971 as a dual tribute to recognize the death of Eisenhower and the Apollo Moon Landing which both occurred in 1969. Convenience of use was an afterthought and the size proved to be its eventual undoing. In 1979, it was replaced by the ill-fated "Carter Quarter", possibly the single worst idea in US coinage history. At the very least, a close second to the 20 cent denomination.
5)Due to the rising use of dollar coins in vending machines and mass transit systems in the 1990s, Treasury stockpiles were dwindling. The Sacagawea dollar was was authorized under the United States Dollar Coin Act of 1997 but Treasury officials feared that supplies of dollar coins would run out before minting of the new golden dollars was to begin in 2000. In order to meet need, a short run of ~41 million SBAs were cranked out in late 1999. So late in fact that the 1999 proof was not included in the regular proof set, it had to be sold individually.
6)The Presidential $1 Coin Act did not replace the Sacagawea series, it was only written to be a primary supplemental series and also decreed that 1/3 of the total dollar mintage be Sacagaweas. The Native American $1 Coin Acta replacement for the Sacagawea series, did little to alleviate the duplication problem but the mintage requirement was reduced to 1/5.
sources: Comprehensive Catalog and Encyclopedia Of Morgan and Peace Dollars and A Guide Book of United States Coins
As you pointed out, confusion was a popular theme but it did not stem from the Mint itself. Actions by the Mint are strictly dictated by Congress and various political maneuverings and machinations were responsible for the confusion and contradictions throughout the years and it still continues to this day.



















