My understanding is that for performance bonuses they count towards this year's cap if there's space but become overages for next years cap if there isn't space this year. However I think the whole saga about using offseason LTIR vs in season LTIR for Price was because by using in season LTIR it would actually cover performance bonuses whereas with offseason LTIR it doesn't.
Anyways since it's interesting to see what Slaf might have as goals here's the standard performance bonuses on an ELC.
Entry Level Contracts are eligible for Performance Bonuses. There are two categories of Performance Bonuses: "A" Level Bonuses "A" Bonuses are worth $212,500 each, to a maximum of $850,000 (maximum 4 achieved). For players signed starting in 2022, "A" bonuses are worth $250,000 each, to a...
puckpedia.com
The ones still relevant for Slaf are
Finish top six in ice time for forwards which should be pretty much in the bag
For goals he'll need 8 goals in the final 27 games which certainly seems quite likely
For assists he'll need 17 in the final 27 games which is probably a little harder but still doable
For points and ppg he'll need 30 in the final 27 games which will be quite tough
There's also the +/- one but who knows as that requires not only Slaf to do well while somehow doing better then his linemates and others to start dropping, and at the end of the day getting lots of ice time on a bad team means a bad +/-.