The mist that you saw was hydraulic fluid, commonly called Skydrol. The only other possible mist would have been jet fuel, but you would have known that was it form the smell. The hydraulic fluid is clear as well. It doesn't have that unique fuel smell, but it does have a funky smell. As far as effects from it, you should be fine. It does burn like hell if you get it in your eyes and such. But I've seen several occasions where guys have gotten Skydrol in their eyes and mouth before, and never had any effects after they got it flushed out of their eyes, etc. Basically if there were going to be any harmful after effects you would have had them by now, and it wouldn't be subtle either.
Here's a bit of info from the manufacturer of Skydrol.
Skydrol Info
As for all the masks not dropping, I would say there wasn't actually a loss of cabin pressure. Trust me, you would have noticed. Anytime you have a decrease in pressure, you have a decrease in temperature. With a depressurization of an aircraft, it's sudden, and so is the temperature drop. As a result the cabin will instantly fill with fog caused by the air suddenly releasing it's water vapor. Also your ears would have popped. I've had a couple occasions to sit with a mechanic when he had to pressurize the cabin while on the ground. Both times when he was done, he opened the air outflow vent pretty quickly. It wasn't enough to cause the masks to drop, but that cabin got cold real fast, and once there was a bit of mist in the air.
And trust me, half of those masks would not have failed to drop if it were in fact an actual loss of pressure. Spirit has a brand new fleet these days. I'm not sure how old the oldest plane is, but it's not more than about 5 years old or so. If there was a pretty good jolt of some sort it can knock them open. The one's on the Airbus are also not the best latches out there. I actually saw one drop open in flight for no good reason.