I've been through a number of survival fusion reactors and I've always been able to get away with as few as 2 Van de Graaffs per reactor, on opposite corners, powered at 1MW each, so I doubt that's the problem.
Just use DC engines for the 2 VDGs. 1MW is massive overkill.
For cooling, there should be one block of air above the toroid magnets machine block itself, then a pipe of liquid nitrogen. In the image, it looks to me like the piping might be too low. WAILA should let you know if the toroid magnets are being filled properly.
It can accept coolant from either of the 2 blocks above the toroid block.
OP:
First, make sure you are on the current major version, as previous versions had some issues that makes things more difficult. ( V9 is what you need. Currently 9b, soon to be 9c. )
Also, be aware the power numbers in that video are all wrong, and are WAY higher than you need.
In the DragonAPI config, turn on Hold TAB to show NBT data, then go up to your toroids, and hold TAB to get all of the details that matter.
Solenoid: should be 1b. If it is 0b, the solenoid check is failing. It needs 256r/s and 32,768 NM of torque.
The middle solenoid block needs to be on the same level as the toroid magnet blocks.
Next: should be 1b. If it is 0b, the completeness check is failing.
This means your toroids are not properly aligned, or one or more of your injectors is facing the wrong direction. ( They all need to face the same way. )
Coolant: Anything over 0 is enough. Be aware that once you get it working, the coolant levels will start falling. Your current setup will likely need more LN2 reservoirs to keep up with demand.
Charge: Anything over 0 is enough. This is one of the places people WAY over shoot. 2 VDGs at opposite sides with 1 DC engine each is enough. If you feel like being safer for some reason, just go with 4.
Also, your absorber wall is going to melt, and a large amount of them will never do anything. I recommend some sort of ring design, and have boilers on both sides of the absorbers.
You also only need 1 preheater for all of your injectors. ( Up to something like 50 injectors. ) 2MW to power the heat ray, and a VDG with a DC engine for every approx 30 magnetic pipes. ( If placed in the center obviously. )