Neither one of the sources you quoted could even remotely be considered "cites" (which term would be to authority directly from Congress, Treasury Department, or IRS).
Regardless, although you can stress as much as you like about the date at the top of the return, for a trust (1041) that is not selecting a fiscal year, you can simply select "calendar year" and file on that basis.
Calendar years generally end on December 31st and returns for calendar year trusts/estates are normally due April 15th (but due July 15th for 2019 fed returns - check state due dates below), so the point here is actually moot.
https://blog.turbotax.intuit.com/tax-news/is-the-tax-deadline-delayed-what-to-know-about-coronavirus...
[Edited 3/25/20 to reflect IRS extended 2019 dates]
