How were the celtic warrior-goddesses macha, morrigan, and badb similar to the valkyries in norse mythology? how were they different?

They were all strong independent warrior woman and goddesses of power,war, and the afterlife. Viking women had more rights than other European women during that time period. The property that a Viking woman brought into her marriage remained hers and did not become part of her husband's estate. Viking husbands placed enormous trust in their wives, and the children of free Viking women were protected by Viking law and were deemed the property of their mother. 

Morrigan, also known as Morrigu, is the Celtic goddess of death and destruction. It is usually depicted with armor and weapons. Morrigan is present in all wars, taking the form of crow or crow. According to Celtic mythology, Badb is a goddess of war who could be transformed into a "crow". It is sometimes called Badb Catha ("Raven of War"). It is said that it can also acquire the form of a wolf Macha It is a complex Celtic divinity. "Macha" means field or plain for what is directly related to the land, to the rural; although the term field can also refer to the battlefield giving a sense to the earth as a warrior and mother of the gods. The Valquirias were disir, minor female entities that served Odin under the command of Freyja, in Norse mythology.Their purpose was to choose the most heroic of those fallen in battle and take them to Valhalla where they became einherjer.

As a summary we can say that all these deities are represented by strong, independent women, and warriors, all have the same objective to serve on the battlefield.

Although all these deities are independent, we can say that the Valkyries serve a God with the form of a man superior to them, Odin. and the Celtic deities are totally independent, they do not serve a superior god.