Display unlimited galleries of YouTube videos in any post or page within your site.
As many as you want.
Generally, yes, except in cases where the video it set to disable embedding.
Yes, all YouTube and Vimeo videos should work unless embedding has been disabled.
Yes, Even though the plugin is named uTubeVideo Gallery, Vimeo videos are now supported also.
Yes the video player size can be set in the 'General Settings' section in the settings page.
Just go to edit the video in question: edit the thumbnail type and save changes.
After adding at least one video to the album click on the edit link for the video album and select a thumbnail and then click save changes.
There is an option called Display Type in each gallery's settings; set it to Just Videos.
Do to programming constraints and such it seems around 80 videos is the limit, but you will have to experiment to find what works best for you.
If your permalink status is not Ok, it means permalinks are not enabled correctly. Check to see that you have permalinks turned on for WordPress and if this does not fix the problem, de-activate and re-activate this plugin. It's also possible your the settings for your sites permalink structure are not completely compatible with this plugin.
A user must be an editor or above in order to manage video galleries and change settings.