Snuffulufugus

Well I am not sure that I should be the one to answer your questions but I can try. I have played all of those except for Pokemon Uranium so I will only speak to the last 3. Pokemon Zeta is completely finished with two distinct regions and many many hours of gameplay. It is not super difficult and has a pretty good story. I would personally you try this one first as it is the easiest of the three to pick up and play. Pokemon Reborn is by far the hardest fan made game out of all of these, however I found it to be the most rewarding. Sometimes the game feels like it is out to get you however that makes victory all the more sweeter. It is not complete but you will pour many hours into the game before you get to the latest chapter. Again this game is far harder than the others ones so only do this one first if you are looking for a challenge. Pokemon Insurgence is created by the same people who made Pokemon zeta/omicron. This is their second attempt at a fan made game and it shows in how the game feels polished. You are right about the quintuple baddies making for an interesting story. However this game is the most recent and this current release of the game is not super long. Only a few of the gyms have been released thus far. By no means am I saying don't play this one however you should keep in mind that it is shorter than the others.