Brake/ABS/VSC etc lights - What do I do?

I've got an 07' Prius with 225k miles on the dash and I'm in a predicament. This summer I drove the car on a big road trip out west over some 5k-ish miles, during which I had a few hangups. The biggest being a wheel bearing which I wound up replacing in a parking lot in Utah. I'm very experienced with regular cars so I've been doing my maintenance how I would on a typical vehicle - and it's not going very well.
After replacing the wheel bearing my dash was lit up with the ABS, VSC, BRAKE, and (!) lights. I figured it was the speed sensor not reading properly, since that little dust shield around the axle had gotten bent up in my hurry, and so the next day I tore it all down again, removed the dust shield, and reassembled everything to no avail. All the mechanics in town were booked up, so I drove it like that about 4 hours to salt lake city where I had a shop take a look at it. Their diagnosis was a bad speed sensor and an axle that needed replacing (I had nicked the boot on my second reassembly) for which they quoted me $1,000! And for that I told them to pound sand, and I would drive it home to Pennsylvania like that for $1k.
After they reassembled it, however, all the lights were off, and I was able to finish my trip and drive all the way home with a superglue patch on the axle boot and some only minor hiccups. Once arriving home, I ordered both front axles, the other wheel bearing, and a pair of axle seals for good measure (for well under $300). After replacing all the parts (again, like a normal car), I turned my Prius back on to find all my lights had returned again. Following this, I replaced the driver's speed sensor and the driver's caliper, both which I thought might be damaged from my parking lot debacle, and both to no avail. I had the codes read at a local shop and it came up with the following:
B1660 - Passenger airbag mode indicator
B1816 - Open circuit in passenger airbag squib
P0420 - Clogged catalytic
(I'm assuming airbag codes are from having sent out my combination meter for repair during my axles/bearing replacements and moving the car with the dash disassembled. The cat code has been there for a while, and is another issue which is on the back burner right now)
and the important one!
C1342 - Malfunction in hydraulic system (front left)
Online resources tell me this is possibly due to:
-Fluid leakage
-Faulty Brake Actuator Assembly/related circuits
-Worn brake pads/rotors
-Drop/increase in line pressure
etc etc.

So basically my question is this: What should I do? I'm trying all I can to avoid taking it to a dealer - with all the other minor problems I'm sure they're going to try and squeeze me for anything they can, and I'm deep enough into this to want to see it through. I've read online that these problems can happen from not disconnecting the 12v battery when removing the calipers (guilty, oops), or from improper brake bleeding (also guilty - did it like a normal car!) or a spread of other issues. I also read in a Prius repair manual that the recommended steps for troubleshooting start with bleeding the brakes (properly) and then clearing the codes and seeing what new writes, if anything. From posts on here I've seen people mentioning needing Techstream to do this correctly. If I order a MiniVCI, will I be able to diagnose this using the manual troubleshooting steps? Or is it limited enough such that I'll still have to take it to a dealer to have it actually fixed? Is it possible I've already fixed my issue, and just need to clear the old stubborn codes now to get it running properly again? A friend of mine is coming over with a generic code reader this weekend to see if we can make any headway. Any help or hints are majorly appreciated, I want to get this Prius fixed so I can get back to focusing on my other projects.

Thanks for reading.

 

Update: just ordered a miniVCI to hopefully start solving this. Is there anything I need to know about the potentially-malware-infested drivers before I try and install them on my laptop?

 

Not sure what reader they used. It was a Kost tire/auto place I went to. I have a minivci ordered now, so hopefully that will help me through my struggles

As above, I think now I'll just have to wait for techstream to come in and from there try and clear codes/bleed brakes with it