Q&A

First, if the ABS light is on, the ABS is inoperative and that's a safety issue so get it checked ASAP, brake problems are a safety issue.
The other electrical problems could be caused by a faulty ground in part of the system, there's no way to know what that is without inspecting the car. Finding electrical problems is usually the tough part, fixing it, once you know what is, is often easier than finding it.
Here's something on the ABS light:
The ABS light indicates that the computer has detected a malfunction in the ABS system and has diagnostic codes and data stored which would be essential in diagnosing the problem.
A technician with a scanner can access the diagnostic codes and data and then be able to give you a diagnosis.
If you want to find a Toyota specialist, here's our directory link for you:
https://repairpal.com/directory?address=27292&car_bra...

I don't know if this may help, but I have come across a very similar symptom with the front park lights come on when depressing the brakes. It ended up being a double filament bult with the brake light portion shorting out to the tail light portion (inside the bulb). It took a smart old mechanic that knew the cause.