Day of the Dead - Contender's Battling Achievements

[Takaoni]

Doug and I just cheesed these new Day of the Dead achievements and decided that we should share our strategy because they would be decidedly horrible without it.

What you need:
1 friend (good luck Citruss!)
1 (and only 1!) of the Contenders Costumes sold by Chapman in the graveyard of any major city depending on your race. Choose Dalaran or Shattrath to be race neutral.

Form a group/raid and head into an instance (like SoO) so when you die you can release and repop immediately. When you are both wearing the Contender's Costumes you'll be able to damage each other using an extra action button. It will randomly swap between 3 abilities:

1. Quick Punch = 10% health damaged
2. Strong Sweep = 20% health damaged
3. Jump Attack = 30 health damaged (you must back up 10 yards before using this ability to connect with it)

Now just wail away until you have the 50 kills while the other person spam releases. Swap roles and finish up. Note that being fully equipped is better than being naked because all of this damage is % based and you must be able to overcome your default regeneration which is a fixed value until a certain threshold where it converts to a %. If you are doing this achievement in the live environment, though, get naked to take advantage of that.

Advanced Tactics
To make this faster, do a little additional prep:

1. Make a "Naked" gear set and if you don't already have one save a gear set with your normal gear on. You can use an addon to do this gear swapping or the default blizzard version, just know how to quickly swap those sets. If you are using the default you can make a macro like this:
2. /equipset [mod:shift] Naked; Fury
3. Obviously you need to make these names match yours and capitalization does matter with it.

The purpose of this is to lower your own health more quickly, as soon as you release swap to Naked and then back to geared, you should have about 25% health left.
If you are the individual doing the killing, your most efficient path to the quickest kill is using the button until it becomes the Jump Attack and then holding that attack until the health swap is complete. A perfect kill in this regard can take 3 seconds.

Bonus Content: The Macabre Marionette
On your way to pick up your costume, grab Simple Flour and Milk from a major city (note, apparently there is no milk in Dalaran). Buy the Bread of the Dead Recipe and a Orange Marigold both also from Chapman. Using the Marigold will make some spirits visible right near him that will trade you one Marionette for the Bread (again depending on your city choice). For the aggressively entrepreneurial you can do this on every character on your account and cage the resulting extras for selling (most likely later in the year).

[Citruss]

Looking for One Friend to do this with because I have not one

[Kulldam]

Thanks for the tips, Ceetrus and I cranked it out in a couple minutes!