This is a followup to this question. (Matt Feller also mentioned this followup in a comment to the question linked to above.)
For any category $\mathcal C$ write $\mathcal C^{\mathcal C}$ for the category of endofunctors of $\mathcal C$, and write $[\operatorname{Ob}({\mathcal C})]$ for the collection of isomorphism classes of objects of $\mathcal C$. (Note that $[\operatorname{Ob}({\mathcal C})]$ is not necessarily a set.)
Let $\mathcal C$ be a category which is not equivalent to a category having exactly one object and one morphism.
Are the following statements necessarily true?
(1) There is no surjection $[\operatorname{Ob}(\mathcal C)]\to[\operatorname{Ob}(\mathcal C^{\mathcal C})]$.
(2) There is no injection $[\operatorname{Ob}(\mathcal C^{\mathcal C})]\to[\operatorname{Ob}(\mathcal C)]$.
A positive answer to at least one of the above questions would also answer the question linked to above. A negative answer to at least one of the above questions would also answer this older questionA negative answer to at least one of the above questions would also answer this older question. [Emil Jeřábek noticed this mistake.]
(We assume that we are working in ZFC.)