I think Shah is much older than Ceasar... As for the names go, "Ptolemaic" is not an original Greek word, but the anglicised form of "Ptolemaikon" and "Ptolemy" is the A-form of "Ptolemeos"

The "P" is not a "silent" P, but is pronouncedm, in the typical way it goes before "T", like in the Greek word "πτώσις" (ptosis, fall) or "πτύω" (ptyo, spit) or "πτέρυξ" (pteryx, wing).

Seleucid (greek: Seleucides) depends on the school you follow. I pronounce it Seh-leh-f-kee-thes, and afaik it's been pronounced like that in the past c. 2000 years. But the "reconstructed" ancient Greek has it pronounced it like "Seh-lehw-kee-des"