Do the limiters in the multiband sections do anything that might happen too fast for the eye to see... in other words, could they be limiting so briefly that my eye doesn't see the indicator turn on, or do the indicators "hang" for a second when they turn on so they can't be missed?
Yes, it could happen too fast to see in the multiband compressors/limiters. The level displayed is the level in the middle of each block of samples processed. So if you're limiting very fast, it could be that the limiter has already released in the middle of a block while it was limiting at the beginning.
Additionally, when you use "limit before compression" does it actually limit the band and then feed the compressor, or does it affect the way the compressor reacts to the input... and if the second is true, is that channel then actually limited after the compression?
The latter. Limiting is always applied after compression, but with "Limit before compression" the compressor responds as if
the signal has already been limited.