Combining Runtime Complexity Expressions with respect to Dijkstra
Yes, you can just add them together.  If $|E|=O(|V|^2/\log|V|)$, then $O(|V|^2+|E|\log|V|)$ is the same thing as $O(|V|^2|)$, since the first term dominates.  If $|E|=\Omega(|V|^2/\log|V|)$, then it's the same thing as $O(|E|\log|V|)$, since the second term dominates.

It might help your thinking to bear in mind that $f + g = O(\max\{f,g\})$.