3 Books. No idea of their names. PLEASE HELP?

[dozykat]

1st one: Its set with the point of view of a group of badgers.I know a main part of the stories is the badgers on a railway track and a few or one gets killed. I think its a children's book, i remember reading it when i was little and being horrified.

Also does anyone recognise these books, they are both set in wales i think:
Something to do with changelings. I think its mainly about a brother and sister and they call one of the people they live with mam-gu. I think theres a baby in the story too.

or

A story between three? main characters. I think they have Celtic names like Rhiannon and G____??. 2 boys and a girl. I'm sure theres something about them turning into animals like an owl. I think theres a relationship between two of the three.Might even be four characters. Really welsh names.