You're going to run into some square-cube law issues and problems related to biomechanics and engineering safety factors, and those are going to cause significant issues for hard-science:

• Faster & stronger overall, plus longer, thinner limbs means that the torques and stresses placed on the elves bones by their own muscles are going to be a lot closer to the limit of what bones can handle. If you also want the elves to weight less, then the bones are going to need to be heavier. At some point, your elvish bones can't handle the elvish muscles. At that point, there's (at best) zero evolutionary pressure to go further in the direction you're suggesting. Humans already get a lot of sports-related injuries if they're not careful about stretching routines and physical therapy. Your elves will amp that up.
• If you want the elves to leap into / safely fall out of trees and be overall much more athletic than humans, they'll probably need to weigh more and be thicker-boned, not just longer & thinner. Similarly, if they can crush / bite through human bones, they want not just bigger teeth, but heavier jaws, stronger attachment points for the jaw muscles, thicker muscles, thicker tendons & ligaments, thicker skulls to handle the stresses from the oversized jaws & heavy-duty chewing, more robust necks & shoulders to support the larger heads, etc.
• If they're eating more per pound than humans, they're also burning more calories on average - so presumably have a higher body temperature. They'll need ways to shed that heat so they don't cook their brains or other internal organs during periods of heavy exertion. Maybe they've got low (compared to human) limits on their endurance, or maybe portions of their body & brain shut down during exertion to conserve energy and generate less heat. Maybe they're really good at sweating or otherwise managing heat. Long & thin body plans help here, as does a torpor akin to that of hummingbirds.

One way around the above is to build their muscles & bones out of different materials - but that's a harder sell for "evolved relatively recently from a common ancestor". Similarly, you could try to engineer cooling systems that don't rely as much on sweat as what humans have. Maybe copper / aluminum threads their muscles, helping to conduct heat away from the core and adding strength that most organic materials lack. (But how would they get substantial amounts of such material in a primarily meat-based diet? And how much would they have to re-evolve digestive, regenerative & circulatory systems to get such materials where they need to go?) Maybe they have large flaps of skin (like elephant ears) that act as heat sinks.

Maybe they're very limited in climates where they're active, or in what they eat.

The harder you want the science to be, the more concerned you'll need to be about tradeoffs between weight, strength, agility, injury rates, thermal regulation, etc.

You're going to run into some square-cube law issues and problems related to biomechanics and engineering safety factors, and those are going to cause significant issues for hard-science:

• Faster & stronger overall, plus longer, thinner limbs means that the torques and stresses placed on the elves' bones by their own muscles are going to be a lot closer to the limit of what bones can handle. If you also want the elves to be more athletic, then the bones are going to need to be heavier. At some point, your elvish bones can't handle the elvish muscles. At that point, there's (at best) zero evolutionary pressure to go further in the direction you're suggesting. Humans already get a lot of sports-related injuries if they're not careful about stretching routines and physical therapy. Your elves will amp that up.
• If you want the elves to leap into / safely fall out of trees and be overall much more athletic than humans, they'll probably need to weigh more and be thicker-boned, not just longer & thinner. Similarly, if they can crush / bite through human bones, they want not just bigger teeth, but heavier jaws, stronger attachment points for the jaw muscles, thicker muscles, thicker tendons & ligaments, thicker skulls to handle the stresses from the oversized jaws & heavy-duty chewing, more robust necks & shoulders to support the larger heads, etc.
• If they're eating more per pound than humans, they're also burning more calories on average - so presumably have a higher body temperature. They'll need ways to shed that heat so they don't cook their brains or other internal organs during periods of heavy exertion. Maybe they've got low (compared to human) limits on their endurance, or maybe portions of their body & brain shut down during exertion to conserve energy and generate less heat. Maybe they're really good at sweating or otherwise managing heat. Long & thin body plans help here, as does a torpor akin to that of hummingbirds.

One way around the above is to build their muscles & bones out of different materials - but that's a harder sell for "evolved relatively recently from a common ancestor". Similarly, you could try to engineer cooling systems that don't rely as much on sweat as what humans have. Maybe copper / aluminum threads their muscles, helping to conduct heat away from the core and adding strength that most organic materials lack. (But how would they get substantial amounts of such material in a primarily meat-based diet? And how much would they have to re-evolve digestive, regenerative & circulatory systems to get such materials where they need to go?) Maybe they have large flaps of skin (like elephant ears) that act as heat sinks.

Maybe they're very limited in climates where they're active, or in what they eat.

The harder you want the science to be, the more concerned you'll need to be about tradeoffs between weight, strength, agility, injury rates, thermal regulation, etc.