Looking for a sanity check before I start modifying my stair railing and newel posts.

I’m upgrading my builder-grade stair newel posts and could use some advice before I start cutting.

Current setup:

• It sits flush against the stair skirt board on one side
• The post has a slight wobble (not dramatic, but noticeable if you push it)

My plan:

• Butt joints (I don't own a miter saw. yet)

Concerns:

1. Once I wrap it evenly, the post will no longer be flush with the skirt board. Should I:
   1. Trim the skirt back to fit the new pieces?
   2. Move the post over??
   3. Do something else?
2. The post has a wobble at the bottom. What’s the proper way to firm it up before cladding?

I’m not replacing the post, just cladding it. I am replacing the balusters and handrail as-well.

Appreciate any guidance.