Yes for LSD and thallium. I don't see any reliable source regarding the second coming, that sounds implausible to me.
LSD:
Assassination attempts on Fidel Castro (Wikipedia) mention the LSD attempt:
Lacing Castro's radio studio with LSD to cause his disorientation
during the broadcast and damage his public image.
Alleged Plots Involving Foreign Leaders, U.S. Senate, Select Committee to Study Governmental Operations with Respect to Intelligence Activities, S. Rep. No. 755, 94th Cong., 2d sess. PDF
According to the 1967 Report of the CIA's Inspector General, an
official in the Technical Services Division (TSD) recalled discussing
a scheme to spray Castro's broadcasting studio with a chemical which
produced effects similar to LSD
Thallium:
The thallium is mentioned in Conspiracy Encyclopedia (required reading in a 2008 course on conspiracy at Harvard University):
Another was to dust Castro with the depilatory, thallium, so as to
destroy his image by causing his beard to fall out.
Alleged Plots Involving Foreign Leaders, U.S. Senate, Select Committee to Study Governmental Operations with Respect to Intelligence Activities, S. Rep. No. 755, 94th Cong., 2d sess. PDF
The Inspector General also reported a plan to destroy Castro's image
as "The Beard" by dusting his shoes with thallium salts, a strong
depilatory that would cause his beard to fall out. The depilatory was
to be administered during a trip outside Cuba, when it was anticipated
Castro would leave his shoes outside the door of his hotel room to be
shined. TSD procured the chemical and tested it on animals, but
apparently abandoned the scheme because Castro cancelled his trip.
(I.G. Report, pp. 10-13)
Other interesting links:
