I don't have much to add but everyone's comments on the Count and revenge are very interesting. It's true as you say @FuzzyCaoraDhubh that he was more than happy for family members like Valentine to be collateral damage in his grand revenge project, until his affection for Morrel made him rethink... in a similar way to how his affection for Mercedes made him rethink the duel with Albert. He's definitely starting to seem less omniscient and more human again.
I'm also fascinated by the character of Eugenie! I really wasn't expecting to meet a 19th c. lesbian in this book! As you say @DuPainDuVinDuFromage Dumas seems to characterise her as 'masculine' and therefore (implicitly) butch lesbian.
As in this quote: 'So, there we have the second point more or less cleared up', said Eugenie, quite undisturbed, expressing as usual an entirely masculine composure in her words and gestures.
It reminds me a bit of late 19th c./early 20th c. theories of homosexuality as 'sexual inversion', where a lesbian would be perceived as a man trapped in a woman's body. I think that was the theory anyway.
But Dumas doesn't seem particularly negative or judgemental in his portrayal of her. And the statement she makes in the 'Valentine' chapter about wanting to be free in body, mind and heart could be interpreted as a feminist declaration on behalf of women in general, not just on behalf of lesbians.
On another topic I'm wondering if the revenge plot is happening with the villains being knocked off in turn according to ascending levels of guilt. So Caderousse (the most minor player) went first, then Fernand. Maybe next it will be Danglars (who hated Edmond Dantes more actively than Fernand did, I think) and finally Villefort, the most educated and privileged of the baddies.