Felicity's books were set in Williamsburg,Virginia in 1774 and were written by Valerie Tripp. Felicity and her collection were archived in 2011 but she was available briefly after that at the American Girl Washington DC Store.
With a release date of February 9, 2017 the titles are:
A Stand for Independence by Valerie Tripp, which is tagged Colonial and horses.
Love and Loyalty by Valerie Tripp