The U.S. Constitution contains very few provisions relating to the qualifications of Electors. Article II, section 1, clause 2 provides that no Senator or Representative, or Person holding an Office of Trust or Profit under the United States, shall be appointed an Elector. As a historical matter, the 14th Amendment provides that State officials who have engaged in insurrection or rebellion against the United States or given aid and comfort to its enemies are disqualified from serving as Electors.
Illegals are enemies as far as I am concerned, and California has certainly given aid and comfort to them. In a way they are even engaged in an insurrection against the United States that has just been slow and methodical.