What is the ruling on delaying the Fajr prayer until after sunrise due to fear of dogs and thieves? And is that considered disbelief (kufr)?

You are not obliged to attend the dawn (Fajr) prayer in congregation at the mosque if there are legitimate concerns, as jurists have stipulated that fear for one's self is among the excuses for not attending the mosque. However, it is not permissible to delay the prayer beyond its prescribed time. Therefore, it must be performed in congregation at home if possible, or individually. Sleeping through the prayer after its time has begun, knowing that one will not wake up, is an act of negligence and a sin. However, if it occurs before the prayer time, there is no sin, provided that one takes the necessary precautions to wake up.