Is there a minimum salary, and can benefits like housing count toward it?

Your means of support must be secured by the salary from the job. There is a minimum monthly gross salary threshold that the position must meet for the permit to be granted.

Fringe benefits such as accommodation can form a part of the salary package, but they cannot make up the entire amount required, so a sufficient cash salary is still needed. For the exact current figure, always check the official Migri page, since thresholds are reviewed periodically.