by all means, continue outlining ideas.
OK.
I would add 1 of the major element plot point concepts from Babylon 5 into the story. Dropping little hints and ideas along the story that come to fruition as part of the main story later on.
For instance have a group of 50 or 60 Tok'Rah on earth studying the database in Atlantis. Remember despite the success of defeating the Goa'uld they are a dying race with no Queen. It's like a hive of ants or bees that suddenly had the Queen removed and no new eggs to become queens in the future. They would be digging through that database with everything they had in hope of transforming one of their members into a Queen may be more than one.
How would their presence on Earth especially if they managed to transform some of their members into queens affect the future development technological, social and otherwise of Earth B?
There's a certain spotted species of humanoids that live with symbiots that might decide to send an entirely separate envoy to earth B. Separate from any official federation delegation when they hear about a completely different species of symbiote that has different abilities from their own that blend with humans.
Everyone when doing stories like this have a habit of focusing or dare I say fixating on the federation. It might be a good idea to avoid that at least for most of the story. After all Earth B from the stargate universe has had many negative experiences with other human cultures that are quite frankly less alien to them than the federation would be.
Should also take into account the different idiosyncrasies within the various powers social and governmental structures despite what's demonstrated on most of the television shows. A lot of times the aspects that are demonstrated on the show are in some ways misrepresentative of the actual culture and government of the faction. You tend to have to dig deeper into the lore to get the truth behind many star trek factions cultures.
For instance Kardasian government structure is based on family structure. Their family structure is very rigid. So any time they are placed in charge of another race or species they have this same structure encompassing them. If that other race or species is rebellious, obstinate or in any way conflictive with that they are punished in much the same way a child would. Except it's not a child. It's an entire people.
It starts with a Stern talking to with them pointing out what they did wrong and what they should do right. If they continue to be rebellious they are essentially placed in a corner. If they continue to be rebellious after that they are sent to bed without any supper. If they continue the rebellious behavior the punishment continues to escalate. This makes them come off as being very authoritarian against anyone. They come off very much like space nazis.
However this same social structure is extended to anyone who conquers them. They will act as though they are the dutiful child whose mother or father just married a new spouse and they will bend over backwards in an attempt to placate them and Integrate themselves as singlessly as they possibly can into whatever new government structure their new government parent is willing to impose on them.
Another is Klingons. The Klingon Empire comes off as again racist in the Shows. However if you re-watch them with a critical eye you will see that they're not. They are violently meritocratic. Every klingon in a position of power is observed and spied on constantly. This is in case one of their underlings decides to take their position from them. The standard operating procedure for advancement in the klingon empire (this includes even the chancellor who controls the entire empire) is to confront the individual with verbal accusations and physical evidence usually demonstrated by a data pad. That they are incompetent and not doing the job very well. Then proceed to fight them to the death in Malay.
After of which your actions will be evaluated by those in a higher position than the one you just took. At which point if the individual you replaced is found to have been conducting an incompetent job. The job is now yours permanently until as starship troopers said. You either die or somebody better comes along. They don't actually care what species or race you are? This was demonstrated in TNG when Riker took a stint on a Klingon bird of prey. The whole recording clingos in position of power was demonstrated in the original series.
This is the actual reason for the continuous recording. Because somebody has to do a review as to whether or not you were actually in the right to take that person's job. (By the way if they were found to of killed their commanding officer negligently they would be executed so they don't actually advance unless they're sure that the guy above them is incompetent.)
As far as romulans go? They actually allowed a vat grown human clone to become the Ruler of their Empire.
Then there's the Feringi. They are actually ruled by whoever is the richest and owns the most assets. Doesn't matter what race they are. Just have to be a really good businessman. They went so far as to change their own religion when it was realized that the females of their species could actually bring in profit.