Another proof of service question

If someone in her house other than her signs for the paperwork, is that ok? Or do I have to have a receipt with her signature?

An agent can sign for someone- depends on who it was an whether or not that person would qualify as the agent of the other. You may need to eventually try using a process server because then the situation which you descirbed would qualify as service, assuming the person who received the documents at the household was of age.