Marvel Ultimate Alliance 2

This one is a lot easier solo, unlike the others. Whoever you use as your main character, as soon as the mission starts, kill off your partners by jumping off the edge or running into the blue force field behind you. Ms. Marvel is great for this as she can't be hurt by the force field and her power is a direct fire attack so it won't set off the mines or vortex machines. Invisible Woman is great as well since she can just walk by all the enemies. See the video below for a method using her.

If you pick up a mine and it blows up in your hands, this DOES count toward the achievement. You don't actually have to "throw" the mine, just get it off the ground.

This one seems to be a bit easier solo for some reason, unlike the others. Use Thor and as soon as the mission starts, kill off your partners by jumping off the edge or running into the blue forcefield behind you. From there, go into flight and pretty much ignore all enemies, only landing to take out the mines. Some barriers have a mine extremely close on the opposite side, so try using his special to break them from afar, then move in to deal with the mine. Also avoid hitting the vortex machines, as they will suck the mines in and you won't be able to grab them.

If you pick up a mine and it blows up in your hands, this DOES count toward the achievement. You don't actually have to "throw" the mine.