Invite them. An invitation isn’t an obligation – if your friends still don’t feel ready to socialize, they can always decline. And a baptism! Spiritually, an ethos of inclusion and forgiveness ought to be part of welcoming your daughter into the church. Besides, a religious ceremony with all its choreography and solemnity provides a lot of structure and something to talk about, making awkward relationships easier to manage than a more free-form environment would.
That’s the advice you asked for. Do you mind an unsolicited second helping? Because a few red flags stuck up in your letter. For one thing, why are mutual friends involved in this kerfuffle? No one needs to know anything other than that the Atticsons helped you out for a while by letting you live with them, it was awfully crowded, and you moved out. If other friends are feeling that you’re putting them in the middle of your conflict, take some steps to fix that. Also, while you say Mrs. Atticson is still feeling hurt, you don’t appear to have any sense of having hurt her. What’s up with the disconnect? If the relationship starts chugging back to life after the baptism, you may need to sit down and have a good coffee talk with her. Or maybe you have the kind of friendship in which the sharp edges can simply wear down over time. Either way, your continued friendship will depend on the extent to which you can agree on what the story of your three months together is going to be.