I am so sorry for you and your family's loss of your beloved "Ewok".
When it comes to calling out Ewok's name, I think that is fine to do so. You can call out to the memory of your boy or to his spirit.
Several times a day or more I call out to my cat "Marmalade" by name, or by his nickname "Doc", although he has been gone for over 5 months now this week. I tell him Good morning each morning, let him know when I am leaving and when I have returned to the warehouse loft where we resided together and I say "good night" each night before I go to sleep.
The sight of the cedar box which that contains Marmalade's ashes is the first thing I see each morning and the last thing I see each night. I say a prayer for Marmalade and to him each night, before turning out the light.
I am relieved that your Ewok knew such great love in his lifetime and that he was truly a part of a family. Your words express how dear he was to you and I am sure he realized that for all the time that you were together.
Kind regards and my sincerest condolences,