Console Minecraft uses split screen if you play with multiple players on one console. Since Windows 10 edition is practically the same game, it also has this option.
I think Windows 10 edition also allows to play with USB controllers. So you could for example play with one person on keyboard and mouse, three on controllers and a split screen.
I did not confirm that splitscreen actually works, it likely doesn't. There is this bug report for it.
Simpler solution
There is often a better command that can be used instead of /testfor, if you have a pressure plate that should only kill "Player2", you can simply use this command:
/kill @a[name=Player2,x=~,y=~2,z=~,r=1]
This is assuming that you have the command block 2 blocks under the pressure plate.
More general solution with /execute
Whenever you want to use /testfor, you can likely use /execute instead, simply by putting the target selector from the /testfor command into it.
If you want to kill "Player2" if a zombie is within 5 blocks distance from the command block, then you could use /testfor @e[type=zombie,r=5] in a command block and then /kill Player2 in a conditional chained command block.
This could be done more easily by putting the target selector from the first command into an /execute command:
/execute @e[type=zombie,r=5] ~ ~ ~ kill Player2
Even more general solution
In some extremely rare cases I can't think of any situation where you really need anything beyond /execute right now even this may not be enough, maybe you want to execute several commands as a specific group of mobs that may not be detectable with the same target selector after every command.
If you really need something like this, then you can set up a scoreboard objective:
/scoreboard objectives add objectives dummy
You would use one repeating command block that continuously sets the score of all entities to 0, the scoreboard objectives will be used to determine what entities to execute as:
scoreboard players reset * objectives
For every system that you want to set up you would then set the scoreboard score with the same target selector you would use with /testfor, or /execute. Each score value should be unique to every setup:
scoreboard players set @e[type=zombie] objectives 1
You would then use a chain of command blocks, one for each command that you want to execute. You would likely use /execute again, maybe in a command like this:
execute @e[scores={objectives=1}] ~ ~ ~ kill @a[r=5]
This example would kill all players within 5 blocks of any zombie, it could be done more easily with /execute @e[type=zombie] ~ ~ ~ kill @a[r=5].
Best Answer
/summon villager ~ ~ ~ {Invulnerable:1b,NoAI:1b,CareerLevel:1,Willing:1b,Offers:{Recipes:[{rewardExp:1b,buy:{id:"minecraft:rotten_flesh",Count:64b},sell:{id:"minecraft:diamond",Count:1b}}]}}That should solve all you problems. It summons a Villager that trades 64
rotten_fleshfor 1diamond. It has no AI so it wont move around and is invulnerable so it won't die.