According to the book "Mosaic, written by Jeri Taylor, Janeway met Riker at Starfleet Academy. Tyey were obviously at the same age. In that case, Janeway was born in 2335.
According to the book "Star Trek Chronology", written byMichael Okuda and Denise Okuda, both Riker and Chakotay was born in 2335.
As for Tom's accident, according to the book "Pathways", written by Jeri Taylor, three cadets were killed in the accident. On the countrary to Nic Locarno's accident, where the cadets were trying to do a "Kolvoord Starbust", Paris's group of cadets were targeting-shooting at asteroids, Paris made a too-advanced dive which the other cadets couldn't habdle which resulted in two cadets who were trying to follow Tom's moves crashed into the asteroid and the third was caught up in the explosion.
As for the Paris-Locarno mystery, my personal theory is that Nick Locarno was a result of old Owen Paris having an afair with a lady other than his wife. Owen kept quiet about it but supported Locarno so he could go into the academy. There, Locarno messed it up and was kicked out but Owen Paris managed to cover the tracks so that no connection between him and Nick Locarno could be traced. However, Tom found out about it, therefore his dislike and loathe to his father.
As for Nick Locarno himself, according to the novella "Revenant", he was assimilated by the Borg in 2380 (see Memory Beta for further information)
Does that explain why he keeps a picture of Nick Locarno in his cadet uniform on his desk?
