I don't think there's any chance at all they would have taken her back, if by that you mean living at Longbourn with them -- Mr Bennet doesn't even want to have the newly-wed Wickham and Lydia to visit, and that's after it's been patched up! He's certainly not going to risk the reputations of his other four daughters being further hurt by having their damaged-goods sister back living at home. (And there was always the risk she was pregnant, too...) I mean, I bet Mrs Bennet would have wanted to, but Mr B would have overruled her.
Sir Thomas in Mansfield Park tells Mrs Norris, who assumes that the presence of the unmarried Fanny is the reason he won't receive his adulterous daughter back home after it's clear the man she left her husband with won't marry her, that this is not the case, that even if he didn't have a young, unmarried woman living in his house to be 'endangered' by contact with Maria, he would still never have had her home:
he would never have offered so great an insult to the neighbourhood as to expect it to notice her. As a daughter, he hoped a penitent one, she should be protected by him, and secured in every comfort, and supported by every encouragement to do right, which their relative situations admitted; but farther than that he could not go. Maria had destroyed her own character, and he would not, by a vain attempt to restore what never could be restored, by affording his sanction to vice
In his case, money is no object, so a discreet establishment is formed for Maria in a different county, with her aunt Norris to live with her. I wonder what Mr Bennet would have done with Lydia in a similar situation -- some kind of discreet 'paying guest' situation with a family in a remote area?