I don't know what else to add. What else do I need to be "specific and detailed"?

Elaine

Shredded mulch does decompose and add nutrients to the soil.  It has a tendency to compact over time which can hinder water and air circulation.  If your mulch becomes compacted, you should periodically rake or break up the mulch to increase water and air circulation.

You don't need to use pine needles or pine bark mulch for your acid-loving plants unless you prefer that type of mulch.  Pine needles do not acidify the soil any more than other mulches.

Pine Needle Mulch- the Myths and Legends | N.C. Cooperative Extension

If you have additional questions, please contact us.

Yes, you can just rake or break up the mulch instead of replacing it.  You need to make sure that water and air are getting to the soil so you can't just rake the top of the mulch and leave some untouched.  If the compacted mulch layer is thick (3 inches or more) or the raked mulch doesn't do the job of weed suppression or water retention, you might want to consider replacing it.  Sometimes old mulch needs to be removed before applying new mulch so you the mulch layer is not too thick.  But if your soil can get air and water and the mulch is still doing the job, then you don't have to replace it.