1. The metal in the pocket will "self clearance" on the uca near the bushing at the body (~2 inches out). tapping bottom of the pocket with the grinder to remove that metal will also eliminate the problem, spray paint it if you do grind it. Don't need to but nice to do. it will fold the lip on its own.
Sorry no pic. It folds easily from the uca, didnt even scuff the powder coating on the arms where it made contact.
You only need to do the bottom, your likely on your extended bumpstops when stuffed so the roof of the pocket won't make contact with the arm.
edit: just saw page after your question, natural bumpstop seems logical. never thought of it that way.
2. ball joint is assembled with wheel off. bushings on upper control arm should be "finger tight". mount ball joint in its mount, torque the castle nut, put in split pin, put on tire, lower vehicle, bounce it a little. Then torque the bolt that goes inside bushings, 80 ft lbs.
Don't forget to retorque again after a couple hundred miles if your ocd about such things. requires removing battery tray and air cleaner again to gain access, Doesn't take long if you've done it once.
That grease gun will work fine, but buying the full sized one for a better selection of grease options, depending on your evolving needs. The grease is also cheaper in the long run, not that the ball joints require a lot.
I bought the cheap lu max canadian tire trigger operated one for to have a free hand to adjust the ball joint if the zerk isn't taking grease. $12 vs $18. If you have it don't worry about it.
For grease selection to use synthetic grease or marine grease as i'm not a fan of anything with graphite as i'll also use that grease on o rings for electrical connectors or pressure connectors for other types of survey tools. graphite is conductive and makes a mess so i tend to stay away. Any grease is better then no grease so there is not real do not use for that application.