Purification tablets in a keyring pill fob.

I want to remove half a dozen or so MP-1 tablet's from their packaging and put them in a keyring pill fob. The fob has a proper inner container for pills.

Anything that I need to know?

If I remember correctly, the moment you remove an MP1 tablet from its packaging, it begins to react with both the air and whatever container it's in and will soon become useless.

I bought a small Nalgene bottle, epoxied a small plastic loop to the lid so I could hang it off of my caribiner, and put individulal squares of the MP1 packaged tablets in it. Though a small bottle, as part of my key ring it takes up a pretty large amount of space.

You do not want to do that. The MP1 tabs are meant to be kept away from oxygen until they are used. Otherwise the react with the O2 and become useless.
Also YOU DO NOT WANT TO HANDLE MP1 withyour hands ever; it is corrosive.
When I use some I open the package and drop the tab into the water without ever touching it.

Chlorine dioxide and iodine based tablets both are highly corrosive and rely on their interaction with oxygen to work. In a few days, with luck, they'll be at a fraction of their effectiveness if not completely dead. And your pill fob will be the worse for wear.

If you want to play the repack game, iodine tablets are your best bet. You need a small glass (!) vial with a teflon cap or a cap with a teflon septa (little disk that goes in the top of the cap). Don't try to fake it with teflon tape, doesn't work- voice of experience. Although a winding of teflon tape around the threads for security is a good idea. Keep that lid down tight, and keep it in the dark if you have a colorless vial. Keep in mind that once you open the factory vial, the clock is ticking, you've got 6 months, maybe a little more but why gamble it.

A 5/8 dram bottle works well, and you should be able to fit one in a medium sized pill fob. Doug claims he can get 25 or so tablet in one, I can get 18.

It's also worth considering potassium permanganate in this role. It's not great as a water purifier but it's better than nothing, and has other uses too. It comes as small crystals that stain everything they touch if they get wet.

And they'll chew up the steel or aluminum fob just as well as an unwrapped chlorine dioxide or iodine tablet, aren't idiot proof, and are highly reactive....

By all means wrap them.