Anytime you get new rotors you need new pads anyway. And for best anti-fade performance, you should change out DOT3 brake fluid every year or so.
You could go to DOT4 brake fluid to even further reduce the likelihood of boiling it on a long downhill with a trailer, but it might have different viscosity characteristics that might affect the ABS system, especially in the cold.
There isn't anything inherent to slotted brake rotors that would require new brake lines, but I don't think you would be likely to see a performance advantage to those rotors under typical SUV use.