Some call it God's country. I call it Acton, Maine
Too Many - 7 or 8
That center slot is for the Rear brake line, hydraulic or cable. Rocky's come that way. If the rear brakes are cable actuated, they just run housing all the way. There are special clips made to hold the lines, but they end up wearing out fast. A small zip tie will work just fine.
I do not usually say someone is wrong, but Zephyr15 is wrong on this. Those braze-ons are designed as I just stated. That said, you could run a solid rear derailleur housing also. Does not really matter. Regardless, you will have to run one with all housing.