I wouldn't see why that jug wouldn't work since it had water in it previously and if it is properly sanitized. I also use an empty growler myself.
I usually use an empty growler with an airlock adapted lid.
Hopnotch, you should just use a piece of foil placed loosely over the top of the growler as the yeast need oxygen to reproduce. If you're using an airlock they'll be trapped in a CO2 environment. The foil will be enough to prevent contamination.