I have tried, with no success to get either Yoo theme Widget kit (slideshow) or Gavick Image show 4 to work with my slave sites.

I have tried to load a Yoo theme template to work with the Widget kit, but nothing. I am not able to get the images to display.

In addition, I have tried to use them both with the "images" (symbolic) and "images-specific" (fixed) folder location for the images.

Is there a decent image slider for Joomla 3 templates that runs upon install for slaves?

Concerning Yoothemes extensions (Widgetkit, themes, ...) or any extension using the WARP framework, you need to use the "Multisites Patches for Yoothemes".
Yoothemes have bugs in the computation of the path that must be fixed.

www.jms2win.com/en/joomla-multisite?page...46&category_id=1

The issues comes from the fact that Yoothemes bypass the Joomla framework and have redevelop their own stuff that is buggy when using symbolic links.
They use the path of the master that does not match the path of the slave site.
Just because the does NOT use the JPATH_ROOT to compute the path on the css, images, javascript, ....

Okay. I undeerstand there is a patch I could buy specifically for yootheme widgetkit. But is there a frontpage slider that people have used in slave sites that works without patches?

Has anyone had great success with an alternative?

Because the Gavick image module didn't work either.