What to do if you have lots of monitors?

wire all of the power through a fuse(shouldn't need more than 5 amps) to an ignition wire in the vehicle, and all the grounds to one spot, with the small gauge of the wires that you'll use you can probably crimp all of them into one ring terminal.

And I'd definitely get a video amplifier, most have 1 input and 6 or 7 outputs.

pretty much any type of fuse will be fine... ATC, mini, glass tube... it doesn't matter so much as long as the rating is matched (preferred) or just slightly above what the monitors will draw.

Check to see how many amps the monitors draw, add them up, and get a fuse closest to that without going under.

For the most part, I like to use ATC fuses and use insulated female disconnect terminals for fusing along the wire. Walmart and most electronic stores also have quick splice fuse holders that work well too (for about $2)