Federation: Well of course the Americans, what with the USS enterprise etc.
Romulans:... Possibly the Russians reminiscent of Cold war Tensions.
Bajorans: Very Scottish or Irish. Probably Irish!
Clingons: Africans perhaps?
Jem Hadar... Some of these Middle Eastern Groups. Loyalty to the 'founder' is loyalty to 'Islam'.
These are all massively fictionised and in some instances, taken so far away from their original inspiration perhaps, as to be a new thing altogether. Clingons might be an example of this. They became so entertaining they were less dangerous!
However, considering before September 11th it was an open secret that the Americans were funding the IRA... In this fictionalised scenario, the Cardassians are... The ENGLISH!
Cardassians had a very elitest and heirarchical society: Monarchy. They oppressed the Bajorans. I.e. The Irish; and, outside the extremely fictionalised evil of some of the more imaginative episodes, there is just something that is similar in some ways between Cardassians and English society. There is a held backness in English society, a lack of some sort of tactile warmth and a politeness and honour that seems almost genetic. (Or ideally there has been, now there is too much of a drinking culture that is destroying it!) There are definite similarities to the Thatcher Era.
Just an idea. Of course there are variations and cultures change. What was true or fictionalised as true in 1995 might be different to what is so 20 years later!
Don't know about the telepathic race, the empaths. Also... The Borg? The Marquis? The Vulcans? Who knows? Not all of them line up with things in our today society. The Forengi are kind of like the 'customer service' culture. There is definitely strong similarity between the Jewish and the 'Changelings' but I cannot begin to fathom what that one was trying to imply.