I believe it is ok to talk to loved ones who have passed away. My husband passed in 2013 and yes I do have conversations with him even still. I do think that each person must go thru the stages of grief. I don't remember all of them. I wish that I could still remember his voice, and it is ok now that I don't.
I have not written him any letters, it would be difficult for me. I do love the phone booth idea, and also the candle. I know that I will have to go thru the grief emotions when my Mother passes. Which I hope will be a while yet. Thanks for your post.