just few question

Hi,

1) My metadata (title, alt, description, caption) are set ONLY in WP not in Lightroom where they are left blank, I understand that the metadata sync is only one way LR–>WP but there is a way to override this in order to update ALSO my Lightoom metadata? maybe just one time process.

LR Publish Services are one-way. Even though it could be tricked, that would be an ugly solution very prone to issues. The complexity and stability of the whole solution would also take a big hit. But generally you should think your Lightroom library as the reference for all your images data. What if one day you decide to push your photos to another website as well? 🙂

2) It is better to sync after or before change the filename using your renamer plugin, or it does not mater? As for now in my test looks like it does not matter, correct ?

It doesn’t matter.

3) There is something related to WPML that I have to know using WP/LR Sync ?

As you know, there is this WPML Media plugin that I don’t recommend. WP/LR Sync synchronizes one LR photo with one WP media and doesn’t touch the “translations”. The images being the same, it’s totally fine and they are synchronized, and only the main translation get updated with new data (which should be fine as your main language in WP and in LR should be the same).

4) How to upload and works small amount of photos how to sync and publish few photos and not the whole catalog each time?

You can have a look at tutorials about Publish Services but you can’t drag and drop photos in folders, only in collections. You can definitely pick only the photos you’d like to upload, of course 🙂