You are my HERO, Faithful Witness!! Thank you for writing about your experience! You were great about countering their talking points.
Now, what did you learn from your experience? I feel that you discovered that both ladies are converts, they may have authentic personas that are controlled by their cult personas, they are afraid of talking more about the FDS, they want to control the conversation, they feel that you are a worthy recruit, they talk too much, they change subjects frequently, they say that they are willing to research (probably using WTBTS propaganda only), they like eating cookies and drinking tea, and you are becoming better at recognizing when they use thought-stopping platitudes.
What is your plan(s) to keep them coming back, to help empower their authentic personas, and to keep your sanity? To maintain your sanity, I would suggest having appointments or errands to do about 1-1/2 hours after they arrive so that you minimize your frustrations. Ask them simple questions to build a closer relationship with them, such as, "Ask them what they liked about the WTBTS before they were baptized, how WTBTS doctrines have changed over the years, and has the WTBTS done anything that has confused them over the years?"
Remember what your objectives/goals are. Are your goals to help the elderette to critically think for herself or for you to gain experience helping your JW family and friends to critically think for themselves?
I do believe that building relationships with them, asking simple questions about subjects that they are afraid of talking about, and always having something to counter a thought-stopping platitude are your best options. I don't think that you talking more will help. Asking them simple questions when they contradict themselves and to lead them to do independent research of the WTBTS will probably be your most effective strategies. Be patient and compassionate with them as you plant seeds of doubt and learn how to control your emotions as well as peel away the layers of BITE control from them.
Peace be with you and everyone, who you love,
Robert