1) assuming you have the PPU generate an NMI on VBlank (you can enable/disable this in the high bit of $2000, if I remember correctly), the CPU *will* jump to the NMI vector. if not, no big deal. the NMI vector's *value* contains the address to which to jump when NMI is triggered. it is equivelant to JMP ($FFFA)

2) I don't know all the clock cycle bits, although I have heard that it takes "7 cycles to move in and out of an interrupt"; whether that means it takes seven cycles to enter and seven to leave, or seven *total*, I dunno. you'll have to talk to Chris Covell or Memblers or someone else for more info on this.