Prius (2004-09) :: Warning Lights In Cold Weather - Car Seems To Run (mostly) Ok?

It has been cold recently (out of the past week, highs in 20's or lower). This hasn't been as much of an issue before, but in the past week I have had the red triangle of death, brake warning light, check engine light, and VSC light all come on at the same time, three separate times. Also, the display screen shows a red outline of a car with "!" through it. Each time this has happened, the lights didn't come on as soon as the car was "Ready" but only after the gas engine was running for a minute or two.

The first time the lights came on, I was driving back from class, but after I got back to my house I did some internet research and saw it may be a low oil indicator. Checked the oil, it was almost at the bottom mark on the dipstick, and it had been over 10,000 miles since the last one (oops! we don't normally do that). After reading some stories online, I took it in to get an oil change, and the lights went off for a couple days. Second time the lights came on, I checked the oil level, it was definitely over-filled, so I took it back to Walmart and had them redo the oil so that it was at the right level. I checked the oil level before leaving the parking lot that time and it was at the top mark on the dipstick. Again, all the lights were off for a couple days.

Today, I drove my car for about an hour in the morning (temperature was around upper teens, wind chill below 10) and had no problems. Then, this evening I turn the car on and start driving out of the parking lot when the car beeps at me and flashes all of the warning lights again. I drove back to my house and it is now sitting in the driveway. I am not planning on driving it until I can have a car mechanic friend take a look at it on Tuesday, but he doesn't know anything about the hybrid system/battery.

My wife and I have also noticed that since the weather has been colder, the hybrid battery (shown on the "Energy" screen when driving) seems to be charging and discharging much faster than normal. I haven't seen it at only 1 bar or full of green bars more than a couple times in the 2.5ish years we have owned the car, but in the past two weeks it has happened 5-10 times (estimated). I am not sure if this is due to the weather, or if it could indicate a problem with the (hybrid?) battery. For obvious reasons, this makes us nervous :/

As a side note, I changed the transmission fluid sometime in December, so I was wondering if possibly I didn't put enough fluid back in. I have checked the diagnostic screen and found some codes, but most of them seem to relate to the audio, which doesn't concern me as much as the code that seems to indicate the transmission, which is why I mention the change I did a while back. I just don't know why it wouldn't have shown up until now. I'll attach some pictures I took tonight of the codes and lights.

Also, the battery is a couple years old, but after sitting for a couple hours the battery was reading 12.1 V according to the diagnostic screen, so I don't think that is the issue. We haven't had any trouble getting the car to start, and once it is running it still seems to drive normally with the warning lights on. What these codes mean, and a possible cause for the warning lights?