Will these skirts block jack point access?

No. Factory jack points remain accessible — the skirts mount above and do not cover the designated lift areas on the rocker. Verify your jack point location before install to plan placement.

Do I need to drill any new holes to mount these?

No. These bolt to factory mounting points. You will not need to drill into your body panels. Use factory hardware or equivalent fasteners rated for plastic panel mounting.

Can I paint these right away, or do I need to prep them first?

Sand the surface lightly to accept paint adhesion, then apply your chosen basecoat and clear. Standard FRP prep is all that's needed — no special primer or sealer is required if you follow normal automotive paint procedures.