Not tried most of these yet (even on Normal)
but there is no such thing as a mission with only ONE correct method.
What we need is an option to do these without a team and without time limits
THEN people can learn
There is a PUG Infected training mission in the foundry. That mission basically goes through the setps of how to complete Infected WITHOUT the plasma that kills you if you fall off the platforms.
(Jumping and activating the consols)
As for correct methods, activating the three consols and uploading the virus in each corner is a must. That is how you summon Manus. There is ONLY one way you can lower the sheilds around the devices in the four corners of the room. That is by having three people activateing the devices SIMULTANIOUSLY. The difference in strategy is how you go about doing that. I have played in team where all five went from device to device, and I have been in teams that have spread out around the room. In every case, three people had to work in harmony to lower the device sheilds.
Same with The Cure Ground. The three devices, then the four devices all have to be activated. There is no other way to bypass the large force field walls. The differences in methods is how one goes about dealing with the drones that beam in to stop you.
My frustration is getting people to coordinate for lowering the sheilds in either Infected or Khitomer. Unless you have a secret way to go about bypassing those devices, your argument is flawed.