Sylvanborn are Elf/Satyr relatives in about the same way humans are whale relatives, so don't get too hung up on that idea that a Sylvanborn shares many more defining physical traits with an Elf than the ears or with a Satyr than having horns.
The horns have to be pretty distinctly Not Ram Horns, to avoid being confused with a Ram- or Goat-kin at a distance, so the size, colouring, and design might not be allowed to be as close to traditional Satyr as you're hoping; check with your local chapter before coming to game, as the marshals there can probably point you in the right direction to get the aesthetic you're after without breaking the "visibly your Race from a distance" rules.
If you just want to have very hairy legs (such as by using fur pants of some kind), there's nothing stopping you, but you probably wouldn't be allowed to walk around with hooves, and you would probably be chastised in-game by other characters for being naked if you didn't put shorts or pants on over the hairy leg pants.