In the Nov 2019 election, the Democrats won the majority of both Virginia state houses, and there is some discussion that Virginia could be the 38th state to ratify the (proposed) Equal Rights Amendment. (See this law.SE question for discussion of the ERA's possible effects.)
Approval by 3/4ths of the States would normally be enough to pass a Constitutional Amendment, but there are apparently two problems:
Even if Virginia acts as expected next year, there is no guarantee the amendment would take hold. A handful of the states that initially ratified the ERA have since rescinded those decisions and the most recent congressional deadline passed about four decades ago. Despite those roadblocks, activists believe they are well-positioned -- legally and politically -- to push the amendment, which was written by the suffragist Alice Paul in 1923, over the line.
1. Withdrawn ratifications
Apparently four states (Nebraska, Tennessee, Idaho, Kentucky) have "rescinded" their ratifications, after initially approving them, and one state (South Dakota), added a "sunset" provision to their ratification if it wasn't approved in whole by the original deadline.
Are these "take backs" valid? Could they prevent the Amendment from going into effect? How would this question be adjudicated? Is there any relevant case law on the matter?
2. Congressionally-imposed Deadlines
The original resolution by the 92nd Congress included the following preface (emphasis added):
Resolved by the Senate and House of Representatives of the United States of America in Congress assembled (two-thirds of each House concurring therein), That the following article is proposed as an amendment to the Constitution of the United States, which shall be valid to all intents and purposes as part of the Constitution when ratified by the legislatures of three-fourths of the several States within seven years from the date of its submission by the Congress
In 1978 another resolution was passed, extending the deadline to 1982, although this extension was passed by simple and not 2/3rds majority.
Despite these deadlines, the Amendment was ratified by Nevada in 2017 and Illinois in 2018.
Are these post-deadline ratifications (and a hypothetical 2020 one from Virginia) valid?
Would Congress simply need to pass a new (future) deadline, and all the past ratifications would take effect?
Wikipedia does list some purportedly relevant case law, can anyone help me understand how these might apply to these questions?