That brass fitting has pipe threads where it screws into the oil bolt. I'd screw it out, put new pipe sealant on the threads, and then screw it in until it is snug and pointing the right direction. It doesn't need to be very tight, too tight and the brass will break. Any oil that might leak around the threads will go minor, and will drain back to the oil pan with the rest.

The bearings sliding out with the input shaft is pretty common. As long as they are not loose enough to wiggle in the housing, it should be fine. 

Unless the front bearing is in really good shape, I'd replace it. If it has some looseness between the inner and outer races, it will chew up that new coupler you are putting in.