As unconcerned about time as Echo was currently, she wasn't aware of any reason why either Gaia or Mnemosyne should feel guilty. Both had arrived relatively on time as far as she was concerned, the big point being that they had shown up, so any pangs of worry either might be feeling would hopefully evaporate once the realized Echo wasn't upset. In fact, simply having them there made her happier, since she had been hoping to share this happy time with both women of importance in her life.
"Hello, sweetheart," she responded, squeezing the hand slightly as she returned the kiss. Moving aside to include Mnemosyne into their little grouping more effectively, she offered up a smile that said the apology, though unneeded, was most certainly accepted. Today would be a day of happiness, and if anyone tried to bring drama Echo would kick them out herself.
As soon as she spotted the tears forming in Mnemosyne's eyes Echo could feel her own welling up. She was being emotional for a different reason, of that she was sure, but it didn't change the fact that the two women before her were the only ones she felt comfortable weeping in front of. It didn't matter that other people were around; to Echo only Gaia and Mnemosyne mattered currently.