But you don't have to do all that before you go to get your alignment checked. The lean would not normally be enough to skew the readings you need. And it won't effect toe-in enough (if at all) to worry about.
All they're really going to do is set the toe-in anyway usually. Unless you get a real savvy old timer that knows their way around a solid axle Bronco, they'll probably just tell you that all that other stuff is non-adjustable and send you on your way.
But make sure you get the full printout of all of your settings anyway. Even the stuff they say can't be adjusted.
This way you'll know what's up and then you can fix them later if necessary.
Regarding the pitman arm, that's unusual for a '77 to steer good without one, as in spap's case. Lucky guy!
But usually, when using a dropped arm, you need to couple it with a dropped trackbar bracket as long as you're keeping your stock "Y-style" steering linkage.
If you don't have the bracket though, don't worry about it yet. Just get it set up, drive it and see how it handles on the road.
As for the looseness, it could be the angles, but often as not it's a few things on their way to being worn out. You know the bushings are good (you did change the trackbar bushings while you were at it?), but what about the other stuff?
Best test is to put the full weight of the truck on the ground, have a helper see-saw the wheel back and forth just enough to wiggle the tires on the ground. Usually about a 1/4 to 1/2 turn in each direction. Have then do this continually while you watch what's going on under there. You actually want to look at everything, literally from the steering shaft into the box, all the way out to the wheels, to see if anything is loose at all.
Even if it's just a tiny bit, you put a few of those tiny bits together and they add up quick on a short wheelbase tall vehicle.
Paul