The attached zip file contains the WOPs. Remember, THEY ONLY WORK ON MOFI DEMO, NOT THE WA EDITOR/PLAYER. They will not function as anything other than decorative objects when used in WA Editor/Player. Also, not surprisingly, most don't show up correctly in the Editor. I did put in a fake adjuster in each, so that when you right-click on one, you can quickly identify the object as one of the MOFI objects as opposed to an old object type.
Some quick explanation on new objects (note: some MAJOR MOFI SPOILERS

Meteor: this is the "piece of sky falling down" effect in MOFI. You need trigger it via activation from general command (CMD 1). The adjustments are:
ID: the ID you would use for CMD 1
Data0: StartZ
Data1, Data2, Data3: EndX, EndY, EndZ
Basically the meteor will travel from (x,y,z) position (ObjectX, ObjectY, StartZ) towards (EndX, EndY, EndZ), stopping there, with the exception that if StartZ and EndZ are equal, the meteor will keep going even after reaching the destination. So, to make the meteor look like it falls from the sky and hits the ground, you generally want StartZ to be a high positive number, and EndZ to match the destination tile's Xtrude/Height (so 0 for normal ground level).
Magic Shooter: this is the trap that when triggered, aims a spellball towards a specific target (x,y) location. You need trigger it via activation from general command (CMD 1), typically a GC button. The adjustments are:
ID: the ID you would use for CMD 1
Data0: magic (0 = Flo, 1 = Pow, 2 = Pop, 3 = Grow, 4 = Freeze, 6 = Blink)
Data1: target x
Data2: target y
Notice magic #4 is "Freeze" not "Brr". It turns out the game basically uses the same number for both your "Brr" spell, and the permanent "Freeze" spell of the IceFlowers. The difference is apparently solely in who did the shooting. Only the player shoots "Brr"; everything else shoots "Freeze" for magic #4.
Aside from the obvious "trap" uses, you can use this object to simulate having NPCs, Ice Trolls, etc. shoot magic at something other than the player. This is how they did the scene in MOFI where the Ice Trolls attack Stinkers at MakeShift Camp and the green wizard defends with Grow.
Ice Thwart: the closest one can get to an Ice Troll without using the actual Troll model. At least this shoots Freeze. Adjusters are identical to those of Thwarts. Requires custom object texture IceTroll.png
UFO (B): the closest one can get to an UFO without using the actual UFO model. Based on CatHat5678's simulation of UFOs via custom-textured scritters. Requires custom object texture UFOScritter.bmp.
Data0 is the initial direction the UFO moves in (0 = north, 1 = east, 2 = south, 3 = west)
Data1 is turn direction (aka lefty/righty): 0 = turns left, 1 = turns right
rainbow coin: the real deal. Besides looking like rainbow coins, they don't count towards your regular gold coin count, so they don't affect, say, TollGates that count regular gold coins. In other words, they only affect Rainbow Gates (see below). Adjusters are identical to those for regular gold coins.
Sorry they look identical to regular gold coins in the Editor. At least you can tell them apart when you right-click on them.
rainbow gate: Tollgates for rainbow coins. Actually, unlike regular tollgates, the rainbow gate opens as soon as you have collected all rainbow coins. Unlike normal tollgates, for which you have to actually be standing next to one to open. There is no "Cost" adjustment; the cost is simply to collect all rainbow coins.
waterfall: waterfalls are already available in WA Editor, but MOFI also allows you to set Data0 to something besides 0 to get acid waterfalls and lava waterfalls (I forgot which value is which, try 1 and 2).