replied to your chat “A Dance With Aegons”
When did Jon/Aegon get born and infant Aegon get killed? I know it was the same year, but don't know the dates. If 2 year old Aegon was murdered before the birth of Jon, it makes sense that Rhaegar named his new son Aegon. That was the name he had decided for his successor. But if Elia's children were killed after Jon's birth, this is a moot point.
Aegon Prime and his family were killed before the Second Coming of Aegon, but that wouldn’t matter, because Rhaegar was killed before either of those events. So, unless Lyanna independently decided to give her son the name of his recently disinherited and murdered half-brother, Rhaegar would have had to make his inspired naming choice while his first attempt at Aegon-ing was still alive.