is it really BETTER to have them mounted on a non insulating surface?
Yes. Last year, our chassis was a sheet of 1/4" aluminum. We mounted the electronics directly to it, and found it very annoying - it increases the likelihood of accidental shorts, and it means that you have to either tape up or remove sensitive components before drilling holes or making modifications. It's more trouble in the long run than simply making a separate electronics board out of non-conductive material.
is it better to have them mounted on a board that is easily deattachable from the robot?
That depends on how accessible the board is. If you can reach it easily without having to dig through everything else in the robot, not necessarily. If you can't fix wiring easily with the board installed, then make sure you can detach it quickly.
is using velcro to mount each individual component a good idea?
No. The force of bent wires trying to unbend themselves can be sufficient to force components loose from even the heaviest Velcro. We tried this in 2001, and it made a mess. The electronic components all come with holes drilled in them so you can bolt them to things. Use them.
is it not a good idea to mount them to our frame directly using velcro?(our frame is aluminum)
Aside from the usual Velcro concerns, doing things this way makes power distribution a nightmare. If you mount your electronics to their own board, you know that you won't end up needing to mount other things to that, and you won't have to rework your wiring all the time when changes are made to other things.
how easily accessible should they be?
Obviously, you need to be able to access the main breaker fairly easily. For troubleshooting and maintenance purposes, it's a very good idea to make all the other components as accessible as possible. Last year, our electronics were very poorly organized, making it difficult to troubleshoot problems and repair or replace things when necessary. After that, I made sure to make this year's board as neat and accessible as possible, and it's been a dream to work on so far.
is it a bad idea to need to flip the robot over to take out the battery?
Yes. The battery is something that you will want to be able to access very quickly and easily.
has there been any accidents that you know of where any part excluding the motors and fuses had to be replaced completely due to any reason other than physical disturbances?
Battery shorts can make wires melt. Victors are always happy to vent their magic smoke. Crimp connections can fail. Assume everything is unreliable until proven otherwise.
how what gets HOT? the motors..... the victors? well they already have fans on them...
If your gear ratios are good, the motors shouldn't get TOO hot under normal circumstances. The Victors already have their own fans, but you might want to consider putting additional fans near them if your electronics are enclosed in an area that is not well-ventilated.