have to find out the possible forms of the Aramaic noun corresponding to the Hebrew mattanah. The question is whether the first [n] could be kept. From memory, this does not happen in Western Aramaic, but I will make sure. Otherwise, the name is Latin, but with a suitable meaning.
You have made me realise the significance of the name Dositheus. What is given by God is not the person bearing the name. The name itself is attested in the lists of High Priests a few times. It is not common but not rare either. If it was a name favoured by Priests, it would have had to have had the connotation of the gift of the Torah. The Hebrew form in Samaritan sources is always נתנאל nātānel as I remember, but the forms Natan (Nathan) and Yonatan and Mattityahu (short form Mattai) occur as Jewish names, as you know.
Stephan Huller has had a life long interest in religion and spirituality 
dating back to conversations with his grandfather, Gaston Frank. "He said we represent one of the last descendants of the Frankist Jewish faith in the world," he muses. "I grew up thinking that our family was something like the Last of the Mohicans."