A worthy effort! I'm sure there are thread on the Forum that would help. Perhaps some of our members can remember them or know where to search for them.
A quick comment I have is that the names Siddhattha and Sakyamuni are hardly ever used in Theravada. I think Sakyamuni appears a couple of times in the Pali Canon, and I've never seen Siddhattha in the Pali Suttas.