Wouldn't the bonus overage PHI was afraid to incur have only been the $92,500 standard ELC signing bonus?
Can't achieve Schedule A/B bonuses without playing 42 games, so the max overage penalty they would have occurred was $92.5k. Doesn't seem like that was worth it in the end.
On the burning the ELC thing, you still get 7 years of team control if you burn a year after an NCAA season (where you play like 5-10 games in garbage time), and the player ends up in purgatory 10.2C status where they have no arb rights or offer sheet rights.
EDIT: Saw on another thread that Gauthier would be seen as a 19 year old (based on the calendar year that the contract is signed) so it would take 10GP that year to burn the contract otherwise it would slide (see Clayton Keller). Would have been tough to get him to PHI in time to play enough games and PHI would have also had the hammer and could have just played him in 9GP had they wanted to.