Why do the Futurians do anything in 1992 before making Ghidorah?

If you think about it, it was the stupidest thing in the world. Here was what they did, in simple form, as their plan:

1) Get a book about Godzilla, guess where he was made, plan to go back and stop it happening
2) Go to 1992 and find some clever people to take with them to watch them
3) Go back to 1944, stop Godzilla being created by moving him, place Dorats so they can be mutated into King Ghidorah
4) Return to 1992. Chill out for a bit with the humans, until Ghidorah shows up
5) Laugh evilly and say "WE ARE HERE TO KILL YOU ALL", totally taking the character Emi by surprise

This means that the hero characters know how Ghidorah was made, and know who was to blame. If you consider this, it would make sense for anti-time-travel legislation to be put in place and all research on the topic put on hold. No matter what state Japan, the attacked nation, fell into, Ghidorah would be left to trample anything else he (or it?) felt like after the Futurians were done with it. Unless they had some way of killing it (given they created the Dorats, some simple method could have been built into their DNA e.g. a major allergy to some synthetic material they had with them or something). But even so, it wouldn't exactly encourage time travel if we all knew it meant a gigantic monster would destroy Japan. Emi never referred to a method for just killing it off, so I assume the beast would have to be left to run rampant. It hardly seems a nice creature, I think it would kill people.

So lots of OTHER countries would want to prevent it's creation. God only knows what this would mean for time-space-continuum alterations but that's WAY more complicated than I'm going into anyway.

Plus, as well as everyone knowing how Ghidorah was created, they also revealed who created it. They broke loads of time travel regulations I'm sure, and they stole the machine (how the hell do you steal something that big anyway? You can't exactly tuck it under your shirt!). Unless they were greeted as heroes, I would guess that in the future they would not be popular. For breaking laws they would probably be in prison/executed even if people secretly liked what they were doing.

So yeah...why didn't they just do this:

1) Go back to 1944. Stop Godzilla happening, put the Dorats in place (I also query the wisdom behind this; they were pretty feeble creatures and were left for ten years to walk about the wild...unless they grew big teeth and much larger, those things would be ideal for whatever kind of predators live out there)
2) 1954 bomb test creates King Ghidorah
3) Bring their mighty impenetrable fortress of a UFO to 1991; hope no one in the future recognises the licence plate in the description left by observers. Maybe it can even hide underwater or something to avoid that happening at all.
4) Ghidorah does his thing

Personally I would like to know what the hell Ghidorah was doing from 1954-1992. Maybe not many people went near Lagos due to the radiation, and since Dorats were tiny - Godzilla '84 was only 80 metres high, having originally been 12 metres....considering the change in posture the beast took, the original would have been more like 15 if it stood in the way Godzilla did....in comparison the Dorats went from 30 centimetres each to 140 metres - maybe it became a 40 centimetre King Ghidorah and spent years growing. All the same, it took its time.

Maybe they figured it was best to wait till King Ghidorah was big enough to take on the world. But every year they left it growing, unaided (they were, according to the movie, not around from 1954-1992 to guide Ghidorah's growth), it would have been easy for someone to take a pot shot at. Especially living in an island chain that had so few people living in it, countries were happy to use nuclear bombs on it. I mean, couldn't they do it in, say, 1991 instead of 1992 for instance? Personally I would have picked a time when Japan was in a state of economic turmoil, 1992 was a good year for Japan.

And ok so I overthought that entire last two paragraphs....but what do people think about my main point? The fact that the entire visit to 1992 before they went back to 1994 was just pointless?