Why would you want OEM if the park brake has been deleted? You'll end up with that park brake chunk just flopping around looking stupid. Buy a new aftermarket lever with a ball bearing. They're not that expensive.
Early brake lines have a fitting on the end that screws directly into the caliper. Late style calipers use a banjo bolt. Someone on here used the late style lines with the banjo bolts on the early style calipers.
Sure, as long as there's not metal chunks in the bearings, just hose it down with brake clean, carb cleaner, solvent, lacquer thinner, acetone, or whatever. Just make sure you oil the bearings before you install it.
Just make sure you get the cable for with or without TORS, depending on what you have. If the TORS has not been removed, now would be a good time to get rid of it.