Let $G, G_1, G_2,..., G_n$ be groups.
I know the following results:
a) If $G$ is abelian, then $\operatorname{Hom}(G_1 \times G_2 \times \dots \times G_n, G)\cong \operatorname{Hom}(G_1,G)\times \operatorname{Hom}(G_2,G)\times \dots \times \operatorname{Hom}(G_n,G)$
(you may find a proof here: https://ysharifi.wordpress.com/2019/09/26/group-homomorphism-direct-product-1/ )
b) If $G_1, G_2,..., G_n$ are all abelian, then $\operatorname{Hom}(G, G_1 \times G_2 \times \dots \times G_n)\cong \operatorname{Hom}(G, G_1)\times \operatorname{Hom}(G, G_2) \times \dots \times \operatorname{Hom}(G, G_n)$
(you may find a proof here: https://ysharifi.wordpress.com/2019/09/26/group-homomorphism-direct-product-2/)
I was wondering if these results also hold if we replace $\operatorname{Hom}$ by $\operatorname{Aut}$. I believe that they should, since automorphisms are homomorphism, so the proofs from the links above should still work). If they do not, I would be interested if something similar exists for $\operatorname{Aut}$.
EDIT: As pointed out, these results do not hold for $\operatorname{Aut}$. I would like to know if there is something similar for $\operatorname{Aut}$, though.
A little bit more info: when dealing with the number of endomorphisms of an abelian group these results are pretty useful because I can use the structure theorem and then apply them. Now I am interested if something similar can be done for automorphisms.