My thought was that Emma IS Catherine.
I'm not sure, looking at the 1881 image, whether the ditto is meant to apply to Stanley or Townsend, given the name Townsend was added later.
What do you mean by whether Thomas is a Townsend or Stanley? If you believe William's father was Paul then the later children probably were too? Legally, if Catherine never married Paul, they would be Townsends I guess ...