Outcasts/WMG

Carpathia is going to turn out to be Earth All Along
This explains the fossils of hominid species on the planet. The reason that there's radiation in the restricted zone is that it's caused by left over mass nuclear fallout, from the war on old Earth. The ships travelled through time in some manner (possibly the electromagnetic atmosphere around the planet), and landed on Earth in the future. This also explains why there are loads of cut diamonds just lying around on a beach. The duplicates are just images of our heroes from the Earth of the past.

Cass used to be some kind of extremist
This is based on two lines: "I know what you are" and "there was blood on my hands again".

So, the theory: Cass was, at one point, involved in questionable activities for ideological reasons. Could've been religion (any religion), could've been nationalism. However, at some point he "saw the light" and is now a Technical Pacifist / Actual Pacifist. But, with all that stuff on his record, they wouldn't have let him into humanity's all-new last chance, unless he somehow cooked the books...

Cass is gay
What "I know what you are" starts to resemble when the viewer is a cold-hearted bastard. In cold-hearted bastard mode, the argument goes - if you are starting a new colony of humans, and need to start pumping out units, what's the one group you don't want to bring? Answer: the group not oriented to... do the stuff to start pumping out units.

Cass is one of the ACs
It's right there in his name, almost!
 * Nope, but was

Fleur is a time traveller from the future
Carpathia failed in some way, and the survivors sent Fleur back to correct the timeline. She believes in the new settlement so strongly because she has to, because she just came umpteen years across reality itself, leaving behind everything she's ever known. May lead to a Not So Different when it comes out.

Earth is dead, and has been for centuries
The ships from Earth are travelling at sublight speeds with everyone in stasis, and they get thawed out just at the end to land the damn thing. So if Earth was this fubared at the start of a multi-century journey, just imagine what it looks like now...

Carpathia is Caprica 150,000 and a bit years later
Come on, you know it's true. The humanoid fossils/remains, the radiation fields? It's Caprica after continental shift and climate change over hundreds of thousands of years. Maybe "all of this has happened before, and all of it will happen again" doesn't have to specifically mean "robots will turn on you", it could just mean "humans driving themselves to the edge of extinction". This time it's genetically enhanced humans, instead of sentient robots: ACs not AIs!

Alternatively, Carpathia is Kobol 150,000 and a bit years later
Exactly the same as above, but more poetic because it's where humans originally came from. It may also explain the psychic weirdness. Maybe President Roslin's visions weren't drug-induced, but from Kobol itself, and now it's affecting President Tate!

Which means... Fleur is Starbuck reincarnated
She doesn't know it, but it's why she has an affinity for Carpathia and believes in the settlement.

The planet is alive and watching the different factions
Whenever a sentient species evolves it judges them. Should it deem them unworthy it wipes all complex life from the planet via a massive planet wide White Out. The planet will judge each faction and decide it's right to exist before wiping out the unworthy. It stores the memories of the dead, and use them to try and guide them down the right path.

The last sentient species on Carpathia wiped out all life with a super weapon
The radiation and the White-Outs are residual effects of the weapon. In the final Episode they'll find the weapon, and find out that Earth is dead, and it'll be a race by each faction to control/activate/destroy the weapon. It will be activated and the entire human race destroyed.
 * The radiation, I can agree with. But the white-outs seem to just be really bad sandstorms caused by an electromagnetic field.

The signal is a DNA sequence.
4 letters, in a repeating pattern. ABCD. ATCG. It's a none repeating pattern because it's not looped yet.
 * Episode 8: Confirmed

Cass is one of the
Judging by the trailer for ep.8 and the constant hints that people "know what he is", it seems  wasn't the first human to. I don't think he'll be as malevolent as, considering his feelings for Fleur and loyalty to Tate and Stella.
 * Furthermore, episode 7 paints  actions in the pilot in a whole new light. He could have been one as well.
 * Both Jossed as of Ep 8

Outcasts and Primeval are in the same universe.
In the future of Primeval, a catastrophe devastates the Earth, endangering humanity. A space programme to create a fleet of colony ships that will send thousands of humans to a planet in the Goldilocks zone, Carpathia, so Humanity can survive the destruction of Earth. This effort is organised by Richard Tate and Gideon Anderson, they agree that Tate will go on the first ship and manage Carpathia, while Gideon stays and manages the survivors on Earth, helped by his son Matt.

CT-1 arrives on Carpathia and the colonists are overjoyed to find that there are no anomalies on the planet, so far. The colony of Forthaven is set up and a whole new race, the ACs, are created. Terror strikes when an unknown virus, C-23 threatens the colony, killing the Presidents children. The finger of blame is pointed at the ACs and they are ordered to be killed, however Mitchell Hoban spares them. And of course, 10 years after colonisation, the events of the series occur.


 * The Space Programme was supported by the ARC, funded by Prospero.


 * Captain Becker trained Mitchell, Jack and the other XPs before they left Earth.


 * Berger is working with Philip Burton, who is on CT-10...
 * ...also, that Shuttle that arrives on Forthaven at the very end of the series contains a pack of Mutant Future Predators.
 * Philip had CT-9 sabotaged.


 * In Episode 1, Kellerman gives Tate news of Earth, "anyone still down there is not having such a good time of it". He means that the anomalies have finally rendered Earth sterile.


 * Stella mentions the Second Taiwan Crisis, referring to a mass creature incursion.
 * Mastodon stampede in Taipei?


 * When Helen Cutter went missing, she was pregnant with Stephen's child, and when she gave birth, she went back to the present and gave the baby to an orphanage. That baby is either Josie Hunter or her mother or father.


 * Cloning technology is nothing special in both Outcasts and in future Primeval. The cleaner clones are created in the Future, and in Episode 1, Cass shows Stella a cloned piglet.


 * Is the Host Force the creator of the anomalies?


 * Though there's no Outcasts Series 2 coming, I fear Primeval Series 5 could Joss this.