I think the comment about the Orion women given as gifts was more about how in Orion culture the women are the ones in charge and use men as decoy leaders for their operations. Considering their past it only makes sense that these "gifts" are spying and manipulating each of the Great Houses.
Thankfully thanks to the Path to 2409 we know quite a bit of what has led the Orions to this point. With Starfleet cracking down on their activities they threw in with the Klingons to keep from getting shut down. They provide intel to the Klingons and don't raid their ships, and in exchange they were granted some territory within the empire to call home.
I've seen a few bits of information scattered in episodes and lore datachips that indicate the Orions are still scheming around looking to improve on their current deal. A Tal'Shiar outpost indicated that their leader was secretly meeting with Drex (Martok's son) for instance. However since Drex dies in the first KDF episode they will probably have to find somebody else to suck up to (I won't be suprised if it winds up being the Duras family)
Then there is the subjugated Gorn... Defeated and absorbed into the KDF. Since then not many details have expanded on their current situation. I saw a couple episodes in the Reman arc that indicated that the Gorn aren't happy with the current status quo. They are trying to get a voting member on the High Council and when push comes to shove most of them will let their Klingon "allies" die when in a tough battle.
Their siituation is ripe for a rebel faction story arc.
The Nausicans and Letheans have been treated as nothing more than hired mercenaries as far as I know. I recall the Nausicans have a non-aggression pact with the Empire, turning them into privateers against the Federation. The Letheans haven't even been able to get that level of respect from the Klingons.
These two factions desperatly need something to convey their motives.
The Joined Trill are something of an oddity to me, as their main race is part of the Federation (I believe). However since Dax was such a blatant Klingon-phile the devs probably felt they could get away with having them play both sides with the Federation and Klingons.
Finally there are the Ferasans, whose motives totally escape me. As far as I know they are an original creation for this game, as a counterpart to the Caitians from the Animated Series and one of the TMP-era movies.
As far as I've been able to piece together their homeworld is called Ferasa. They were originally one race with the Caitians, but after their own version of an eugenics war, the genetically engineered super-cats won and the normal low bred ones were forced into exile.
However all of that is ancient history and there is no indication what their role in the Klingon Empire currently is. Are they mercenaries, subjugated conscripts, or actual prized allies? You would think that an original creation would get a lot more love from the devs that introduced them.