Round endcaps, joiners, and outline strokes for lines and paths in Keynote?

I have two questions related to creating lines in Keynote because I use many lines to label things in my presentations. First, I’d like to use round endcaps and joiners for lines, as you can do in Adobe illustrator. In April of 2017, there was a post here asking the same question, but the solution that was offered was to use a rounded edge rectangle, but that’s not workable for lines that need to curve, and not easily scalable.

This is from the previous post is is what I'm asking:

Second, I’d like to be able to place stroke around a label line to allow it to show up better; also doable in Adobe Illustrator. The Keynote shadow function is a mediocre solution but only offers a sharp edge one side of the line (and the angle must be adjusted for each line. What I’m doing now is duplicating the line, stacking them, and then increasing the stroke on the bottom copy. That works well, except it’s extra steps (times many leader lines). Plus, without the round endcap, there's no "stroke" around the ends of the lines, which is not what I'm looking for. Keynote finally released the functionality to stroke/outline letters, but I’m wondering if that functionality for lines/paths is just hidden somewhere that I’m not seeing. The other solution is to make the lines I need in Illustrator and then move them to Keynote, but that’s tedious as well. Many thanks in advance!