Tahaarat

Wiping a drop of urine from the toilet seat

Q: There was 1 drop of urine on my toilet seat and I first dried the seat then poured water from the jug carefully over the seat, while pouring the jug of water over the seat, some water leaked off the seat to the sides and down to the floor. Was this water that leaked najis? And also someone stepped on that water and walked across the house. Is the carpet in the house najis?

Salaah becoming qadha due to not making fardh ghusl after becoming baaligh

Q: If a male becomes baaligh by having wet dream and ghusl becomes fardh on him, but he doesn't know that in Shariat you have to perform ghusl after having a wet dream. So he keeps praying with just making wudhu and after 3-4 months of his puberty, he comes to know that ghusl becomes fardh by wet dream. So are all his prayers in these 3-4 months counted or does he have to make qadha?

While offering these prayers again will he make intention of praying qadha prayer or will he make intention of repeating the prayer (I'adah)?