Ive always seen the 4 Empires in this light:
Amarr - Very much an elitist society. If you are above someone on the social ladder then you let them know it, and anyone that isn't Amarr isn't even on the ladder to begin with. They would most likely keep their own religious practices private and just use the scriptures as a way of controlling those that they have subjugated.
Minmatar - Refined savages and fiercely independent. While I believe they are grateful for the Gallente Federations help, I believe they also resent the fact that they needed such help in the first place, and now that they are able they would much rather handle things on their own. As far as members of other races helping them I think that while they are pragmatic enough to not turn them away I don't think they would view them as being a Republic loyalist in the same way they view themselves as Republic loyalists.
Gallente - I really don't know much about the Gals tbh, but I've always thought of them as being Team Gallente: EVE Police. If they see something that they view as wrong, unjust, or cruel then they're up in arms about it. I missed the executions of Enturrier ( if I could get a linky it would be appreciated, all I found on a Google search was the SoE reaction new thingy), but I would imagine that if the Amarr, Caldari, or perhaps even the Minmatar held a similar execution they would most likely condemn it.
Caldari - Pretty much what Vik said. I think they are paranoid of other cultures and perhaps even a bit xenophobic of them as well, but they have their reasons for it. They went to war to keep from being assimilated into a larger culture, and paid a heavy price so I would say that they are definitely on guard to keep something like that from happening again. I don't think they are racist, and actually I think they would be very open to other races that want to integrate into Caldari society as long as they put forth the effort to "toe the line" and contribute to society.
Edit:
Forgot to mention that while capsuleers can change their views on a whim they also grew up in the society they came from. So even if they sever ties and go their own way you cant just negate a lifetime of learning by saying "Fuck you, fuck you, you're cool, fuck you I'm out."