I started shaking my head when seeing the $500 "documentation fee" for the Vibe, but if tax and title is let's say $350, that $5200 total is a $4850 car. I'd like to see that a grand lower, but since it's at a dealer, it probably is around the average ballpark for the mileage and stack of receipts.
Of these choices, I'm partial to the Vibe due to Toyota, receipts, and it's a good "do everything" vehicle. Vibe has good room for what it is, some of that room is probably from lack of seat padding, but it gets the job done. It also has lots of room in the engine bay if things need fixing, and even used transmissions for them are cheap. Just don't buy a manual transmission version unless it's priced right.
The Vibe has most of the Toyota Tax with it, which is bad when buying used, good when selling used. The only exterior problem I know of to worry about is the paint is considered thin, at least on the front of the hood since it gets lots of rock chips, so be sure to look for repainted areas on the car. My only real concern, since it was in the snowbelt, would be if any rust was painted over. And of course take a good look underneath it for rust.
I say the above while not knowing much about the Fusion. I'm cautious of any Ford now due to paint and rust problems, though doesn't sound like you have to worry about rust there. I think Hyundais are good, but less so pre-2012.
Would rather see you get a higher-mileage 2006 Vibe for cheaper than this one, but you're bleeding money on the rental, and apparently there's only so many options right now. Someone needs to mention the irony of the OP working at a car auction yet is having trouble finding a car.
Or just disregard your prior bad luck and get a 2000-ish FWD GM 3.8 with 200k on it for like $1500 or something. Aren't there any Lincoln Town Cars or Grand Marquis there? Assuming you don't mind the mpg and never parallel park.
