Re: option 2 saving money - my time is worth money. An extra half hour commute time adds up to almost an entire 24 hour day over the course of a month. Additionally, from that $400 saved, subtract commuting costs.
I'd go 3, 2, 1, since it's only for 6 months, and save the extra money. I don't think 6 months with 4 females would be that horrible. But as time drags on, and everyone gets more familiar with you, it might really suck - particularly if you're not assertive enough. At that point, you can consider that you'll be allowed to use the bathroom at midnight for 20 minutes; it's out of bounds the rest of the time for you. (Or look at it this way - I've lived with a female for 25 years. I'm out of bed, into the bathroom, shit, shower, shave, and out the door in 25 minutes on work days. I'd be doomed if I couldn't share the bathroom at the same time with that female (wife.) Because, she's in there for roughly an hour; maybe a little more some days, getting ready for work.
4 females, 2 bathrooms? That's at least 2 hours every morning where you'll be crossing your legs if you've got to use the toilet (let alone, get in there to take a shower.)