Is it permissible to perform the ihram for Hajj or Umrah when passing by the Miqat of Al-Juhfah, with the intention of entering into the ritual from home?

There is no harm for someone who passes alongside the Miqat to enter ihram when parallel to it, without reaching the Miqat itself, because their path does not go through it. This applies whether they wear the ihram garments from their home or delay wearing them until they are parallel to the Miqat. This is the view held by the Malikis, Shafi'is, and Hanbalis.